Artículos (Ingeniería Aeroespacial y Mecánica de Fluidos)

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A note on the thrust of airfoils
(Cambridge University Press, 2025) Gordillo Arias de Saavedra, José Manuel; Ingeniería Aeroespacial y Mecánica de Fluidos; TEP103: Mecánica de Fluidos
Here, we show that the thrust force of oscillating airfoils calculated within the linearised potential flow approach by means of the vortex impulse theory coincides with the one resulting from the integration of the unsteady pressure distribution around the solid obtained by Garrick (1936) when the vertical component of the wake velocity is calculated self-consistently and the analysis retains the contribution of the flux of horizontal momentum induced by the starting vortex. The limitations of the self-consistent linearised potential flow approach for predicting the thrust force of airfoils oscillating periodically with small amplitudes but large values of the reduced frequency are also discussed, as well as the reasons behind the ability of other results in the literature to approximate measurements better than Garrick’s theory. In fact, for those cases in which the airfoil oscillates periodically, the flux of horizontal momentum induced by the starting vortex is negligible and the vortices in the wake are convected parallel to the free-stream velocity, we have deduced an equation for the mean thrust coefficient which differs from previously published results and is in agreement with experimental and numerical results. In addition, for those cases in which the airfoil is suddenly set into motion, we have also deduced an equation that retains the effect of the starting vortex and correctly quantifies the transient thrust force.
Stability of finite-length collapsible channel flow to spanwise perturbations
(AIP Publishing, 2024-12) González Herrer, Emiliano; Herrada Gutiérrez, Miguel Ángel; Gañán-Calvo, Alfonso M.; Stewart, Peter S.; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Ciencia e Innovación (MICIN). España; Engineering and Physical Sciences Research Council (UK); Universidad de Sevilla. TEP219: Física de Fluidos y Microfluídica
We consider flow through a finite-length flexible-walled channel formed by removing a portion from one wall of a wide rigid channel and replacing by a pre-tensioned hyperelastic sheet of finite thickness. The flow is driven by a prescribed upstream flow rate which is uniform along the channel inlet, and so with periodic boundary conditions in the transverse direction the system admits a steady state with a wall profile which is deformed in the streamwise direction but spatially uniform in the spanwise direction. Identical to the planar case, this system exhibits two stable static configurations: an upper branch where the flexible wall is mostly inflated and a lower branch where the wall is highly collapsed. We consider the stability of these steady states to spanwise perturbations, showing that both can become unstable to distinct families of self-excited oscillations. In particular, for large spanwise wavenumbers, these steady states are unstable to oscillatory normal modes where the perturbation wall profile has a single oscillating hump in the streamwise direction, not previously seen in collapsible channel flows driven by fixed upstream flux. Furthermore, for sufficiently large wavenumbers and no wall pre-tension in the spanwise direction, this system is always unstable to a new spanwise non-uniform static configuration, which arises due to the merging of a pair of unstable oscillatory normal modes. However, with non-zero spanwise wall pre-tension, there is always a region of parameter space where the spanwise uniform steady state is stable for all wavenumbers.
Beyond Macronutrients Supply: The Effect of Bio-Based Fertilizers on Iron and Zinc Biofortification of Crops
(MDPI, 2025) Nieto Cantero, Juan; García López, Ana M.; Recena Garrido, Ramiro; Quintero Ariza, José Manuel; Delgado García, Antonio; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Iron (Fe) and Zinc (Zn) deficiencies in crops pose indirect problems for human health. The risk of these deficiencies increases with high doses of phosphate fertilizers. Fertilizers obtained through recycling—so-called bio-based fertilizers (BBFs)—can contain significant amounts of Fe and Zn, which can contribute to crop biofortification. Although the use of some organic BBFs has been shown to improve biofortification, an in-depth study on this effect and on the effect of P on Fe and Zn nutrition with the use of different kinds of bio-based P fertilizers is still lacking. A pot experiment with 11 different BBFs was conducted using two soils with different physicochemical properties that affect P, Fe, and Zn dynamics (one rich in CaCO3 and the other rich in Fe oxides) to assess their biofortification effects on wheat and sunflower. Although some BBFs increased Fe concentration in the edible parts, the overall trend was towards an increased P:Fe ratio (up to 62%), which decreased Fe digestibility. On the other hand, all BBFs led to Zn biofortification, with a 27% decrease in the P:Zn ratio in the CaCO3-rich soil, while in the Fe oxide-rich soil, the decrease was up to 61%. The supply of Zn and organic C, as well as the dominant P forms in BBFs, were the main factors explaining Zn biofortification. Bio-based fertilizers also decreased the antagonism between P and Zn and between Fe and Zn. The results demonstrated that the inclusion of BBFs in agrosystems management can contribute to improving the quality of human diets, at least with regard to Zn intake, while also contributing to more sustainable fertilization practices.
Innovation ARIMA models application to predict pressure variations in water supply networks with open-loop control. Case study in Noja (Cantabria, Spain)
(Elsevier, 2025) Muñoz Rodríguez, David; González Ortega, Manuel Jesús; Aguilera Ureña, María Jesús; Ortega Ballesteros, Andrés; Perea Moreno, Alberto Jesús; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Water utilities are increasingly concerned about losses, leaks, and illegal connections in their distribution networks. Pressure control is typically managed through pressure reducing valves (PRVs) with electrically controlled actuators based on predefined tables according to the pressure at the critical point control (CPC). This open-loop control method lacks direct feedback between the PRV and CPC, making it challenging to distinguish whether pressure variations originate from normal head losses or abnormal network conditions. Unlike traditional applications of ARIMA focused on water demand forecasting, this study explores its novel use in pressure management within distribution networks, aiming to predict P3 (CPC) pressure based on head losses across a defined hydraulic sector. To achieve this objective, a predictive model based on the Box-Jenkins methodology and its variations is implemented to analyse time series data. An action path is established to determine the optimal model—ARIMA, ARMA, ARMAX, etc.—which is subsequently validated using real operational data from Noja, a coastal town in northern Spain characterized by significant seasonal population fluctuations. By accurately forecasting CPC pressure, this system enhances the detection of anomalous patterns, enabling more efficient network pressure management. The study demonstrates the potential of advanced modelling techniques in optimizing water distribution networks, providing valuable insights to improve system efficiency, reliability, and sustainability in urban environments.
On the assessment of channel deepening impacts in micro-meso tidal estuaries: A systematic analysis
(Elsevier, 2025-07) Martín Llanes, Guillermo; López-Ruiz, Alejandro; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Ciencia e Innovación (MICIN). España; Consejería de Transformación Económica, Industria, Conocimiento y Universidades. Junta de Andalucía
The need for efficient maritime transportation in estuaries has led to the development of diverse dredging strategies to accommodate vessels with deep drafts. Most recent studies assessing the environmental impacts of channel deepening use advanced, tailored models to simulate the long-term response to historical bathymetric changes in estuaries worldwide. However, these models are often time-consuming and highly specific to local conditions, limiting the broader applicability of their results. In addition, a common limitation is the significant time gap between the bathymetric data used, often exceeding 100 years. This makes it challenging to quantify the effects of isolated deepening operations, which is essential for understanding the influence of human intervention on estuarine dynamics. To overcome this limitation while ensuring efficient and adaptable modelling, this paper presents a three-dimensional idealised model (Delft3D) to quantify the short-term, e.g., weeks, hydrodynamic and salinity response to dredging operations in micro-meso tidal, well-mixed estuaries. Implications on channel operativity are also discussed. The numerical experiments examine variations in both channel depth and dredging length. Key findings suggest that dredging length is critical in the estuarine response. Specifically, dredging length has a greater influence on tidal amplification than channel depth. Changes in the flow structure are primarily driven by changes in the barotropic pressure gradient and bed shear forces, which vary spatially along the estuary, defining three distinct regions of behaviour. In addition, salt intrusion increases linearly with channel depth and becomes particularly sensitive to dredging length in shorter operations. Regarding basin management, results reveal that landward operativity is compromised by dredging in the lower river.
Diagnosis by SAM Linked to Machine Vision Systems in Olive Pitting Machines
(MDPI, 2025) Villanueva Gandul, Luis; Madueño Luna, Antonio; Madueño Luna, José Miguel; López Gordillo, Miguel Calixto; González Ortega, Manuel Jesús; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Universidad de Sevilla. Departamento de Ingeniería Gráfica
Computer Vision (CV) has proven to be a powerful tool for automation in agri-food industrial processes, offering high-precision solutions tailored to specific working conditions. Recent advancements in Artificial Neural Networks (ANNs) have revolutionized CV applications, enabling systems to autonomously learn and optimize tasks. However, ANN-based approaches often require complex development and lengthy training periods, making their implementation a challenge. In this study, we explore the use of the Segment Anything Model (SAM), a pre-trained neural network developed by META AI in 2023, as an alternative for industrial segmentation tasks in the table olive (Olea europaea L.) processing industry. SAM’s ability to segment objects regardless of scene composition makes it a promising tool to improve the efficiency of olive pitting machines (DRRs). These machines, widely employed in industrial processing, frequently experience mechanical inefficiencies, including the “boat error,” which arises when olives are improperly oriented, leading to defective pitting and pit splinter contamination. Our approach integrates SAM into n CV workflow to diagnose and quantify boat errors without designing or training an additional task-specific ANN. By analyzing the segmented images, we can determine both the percentage of boat errors and the size distribution of olives during transport. The results validate SAM as a feasible option for industrial segmentation, offering a simpler and more accessible solution compared to traditional ANN-based methods. Moreover, our statistical analysis reveals that improper calibration—manifested as size deviations from the nominal value—does not significantly increase boat error rates. This finding supports the adoption of complementary CV technologies to enhance olive pitting efficiency. Future work could investigate real-time integration and the combination of CV with electromechanical correction systems to fully automate and optimize the pitting process.
Development of a computer vision-based method for sizing and boat error assessment in olive pitting machines
(MDPI, 2025-06-13) Villanueva Gandul, Luis; Madueño Luna, Antonio; Madueño Luna, José Miguel; López Gordillo, Miguel Calixto; González Ortega, Manuel Jesús; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Universidad de Sevilla. Departamento de Ingeniería Gráfica; Universidad de Sevilla. AGR280: Ingeniería Rural; Universidad de Sevilla. AGR278: Smart Biosystems Laboratory
Table olive pitting machines (DRRs) are essential in the agri-food industry but face significant limitations that constrain their performance and compromise process reliability. The main defect, known as the “boat error”, results from improper olive orientation during pitting, leading to bone fragmentation, pulp damage, and potential risks to consumer safety. Traditional quality control methods, such as the use of flotation tanks and expert sensory evaluation, rely on destructive sampling, are time-consuming, and reduce overall productivity. To address these challenges, this study presents a novel computer vision (CV) system integrated into a commercial DRR machine. The system captures high-speed images of Gordal olives (Olea europaea regalis) just before pitting; these are later analyzed offline using a custom MATLAB application that applies HSV-based segmentation and morphological analysis to quantify the olive size and orientation. The method accurately identifies boat error cases based on angular thresholds, without interrupting the production flow or damaging the product. The results show that 97% of olives were correctly aligned, with only 1.1% presenting critical misorientation. Additionally, for the first time, the system allowed a detailed evaluation of the olive size distribution at the machine inlet, revealing an unexpected proportion of off-caliber olives. This contamination in sizing suggests a possible link between calibration deviations and the occurrence of boat errors, introducing a new hypothesis for future investigation. While the current implementation is limited to offline analysis, it represents a non-destructive, low-cost, and highly precise diagnostic tool. This work lays the foundation for a deeper understanding of DRR machine behavior and provides a framework for future developments aimed at optimizing their performance through targeted correction strategies.
Recycling Manure as Vermicompost: Assessing Phosphorus Fertilizer Efficiency and Effects on Soil Health Under Different Soil Management
(Springer, 2025) Nieto Cantero, Juan; García López, Ana M.; Recena Garrido, Ramiro; Quintero Ariza, José Manuel; Delgado García, Antonio; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Vermicompost from organic wastes can provide nutrients and benefits to soil health. Its effects on P availability to plants is still poorly understood, specially under different soil management practices. This work aimed to assess vermicompost as a P fertilizer able to enhance soil functioning. Phosphorus forms of vermicompost were studied by 31P NMR and chemical P fractionation to explain its efficiency as fertilizer. This efficiency was assessed with a pot experiment using soil from two different soil management (conventional tillage–CT – and non-tillage–NT–) and from two depths (0–5 and 20–40 cm). Under NT, the soil showed a higher initial P bioavailability than under CT. In vermicompost, 65% of total P corresponded to ortophosphate, meanwhile 35.4% was extractable with neutral ammonium citrate. Overall, vermicompost increased the physiological P use efficiency by 87% compared to mineral fertilization, this increase being greater under CT (107%) than under NT (70%). Replacement values on a dry matter basis close or even higher than 100% were observed under CT and in subsurface soils under NT, conditions with the lowest P availability to plants. Vermicompost boosted microbial diversity in soils (by 8% according to Shannon index) and alkaline phosphatase and phytase activities, specially under NT. Vermicompost increased Fe and Zn uptake, while decreased the P to Zn molar ratio in spikes. Vermicompost can be a suitable replacement for P mineral fertilizer, in particular in soils with low P availability, providing further benefits such as improved Fe and Zn nutrition and increased microbial diversity and P cycling capacity in soils.
Assessing microbially mediated vivianite as a novel phosphorus and iron fertilizer
(Springer, 2024) Eshun, Lordina Ekua; García López, Ana M.; Recena Garrido, Ramiro; Coker, Victoria; Shaw, Samuel; Lloyd, Jonathan; Delgado García, Antonio; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Background Microorganisms can transform phosphorus (P)-enriched iron (Fe)-oxide sludge into products with higher P concentration or can directly promote the precipitation of P-rich compounds from water. However, there is no evidence of these products’ efciency as fertilizers. This study aimed to assess the efectiveness of microbi ally mediated vivianite (biovivianite) as P and Fe fertilizer for durum wheat and white lupin, respectively. Results To this end, two completely randomized block experiments were conducted with wheat (phosphorus (P) experiment) and white lupin (iron (Fe) experiment). The P and Fe sources used included biovivianite produced by microbial reduction of P-containing ferrihydrite at pH 6.5 (VivInsol6.5) and pH 7.0 (VivInsol7.0), biovivianite pro duced with soluble Fe(III) citrate (C6H5FeO7) in the presence of soluble phosphate at pH 7 (VivSol), and vivianite from a commercial company (ComViv). Potassium dihydrogen phosphate (KH2PO4) was used as a reference fertilizer in the P experiment, and Fe-EDDHA and Fe(II)-sulfate (FeSO4.7H2O) were used in the Fe experiment. Total P uptake by wheat plants from the product dominated by vivianite and phosphate-green rust (VivSol) was not signifcantly diferent from KH2PO4. The relative P use efciency, i.e., the equivalence in terms of P recovery of VivSol was 74% of KH2PO4, making VivSol the efective P source for durum wheat among the products tested (aside from KH2PO4). For Fe uptake, product dominated by vivianite and metavivianite (VivInsol7.0), was the most efective Fe source for white lupin followed by Fe-EDDHA, ComViv, and VivSol with VivInsol6.5 as the least efective but without signif cant diferences with Fe(II)-sulfate. The average crystallite sizes of the biovivianite were 59 nm, 63 nm, and 66 nm for VivSol, VivInsol7.0, and VivInsol6.5, respectively. Conclusions The mineral constituents of the biovivianite coupled with their nano-crystallite sizes explained its efectiveness as P and Fe fertilizers. The results reveal that biovivianite production is a novel way of producing efcient P and Fe fertilizers from P-enriched Fe sludge or P-rich water. Thus, it can be used for producing fertilizers with high P and Fe concentrations from water purifcation, providing new tools for a circular economy approach in the use of a non-renewable resource such as P.
Modeling Probabilistic Safety Margins in Convective Weather Avoidance Within European Airspace
(MDPI, 2025) Núñez Portillo, Juan Manuel; Franco Espín, Antonio; Valenzuela Romero, Alfonso; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP945: Ingeniería Aeroespacial
This paper presents an ensemble of observed safety margins for aircraft deviations due to convective weather in European airspace. Leveraging historical high-resolution traffic and weather radar data from the FABEC and UK-Ireland FAB regions, meaningful lateral margins are determined based on composite reflectivity and echo top data. These margins enable the estimation of probability distribution for safety distances, supporting both deviation discrimination and lateral separation assessment. Cross-validated results compared against standard binary classifiers and deterministic baseline models indicate that the model effectively distinguishes deviations from non-deviations and accurately estimates lateral margins. This framework enhances understanding of pilot decision-making, contributing to more informed air traffic management and aviation safety strategies.
Two-dimensional global stability analysis of elongated bubbles moving in a horizontal tube
(American Physical Society, 2025) Magnini, Mirco; Herrada Gutiérrez, Miguel Ángel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Engineering and Physical Sciences Research Council (UK); Ministerio de Economia, Industria y Competitividad (MINECO). España; University of Warwick
The linear stability of an elongated axisymmetric gas bubble transported by a liquid in a capillary tube is analyzed through the use of numerical simulations. The study focuses on the influence of inertia, characterized by the Reynolds number (Re) and the imposed flow rate, characterized by a capillary number (Cal), on the stability of the bubble tail, which exhibits ripples at high Re. The numerical approach utilizes a boundary-fitted method in a reference frame anchored to the bubble, combined with a mixed spatial discretization based on spectral collocation in the radial direction and finite differences in the axial direction. This framework enables the computation of steady nonlinear solutions through a Newton iteration scheme and facilitates the linear stability analysis of these solutions. Direct numerical simulations using the volume of fluid method in OpenFOAM are also performed to corroborate the results of the stability analysis. We perform systematic simulations for Cal = 0.005 − 0.04 and observe that the system becomes unstable, with the emergence of oscillations at the rear of the bubble, when the Reynolds number grows above a critical value, designated as Re∗; this critical value is dependent on the capillary number. The instability is due to the increased inertia of the recirculating flow in the liquid behind the bubble, which impinges its rear meniscus. A modified Weber number Wep, based on the relative velocity between the external flow and the bubble, is introduced to describe the competition between the destabilizing pressure force acting on the bubble rear and surface tension. Our results show that the bubble dynamics become unstable for a critical value, We∗ p ≈ 3.65, which remains quite uniform across the range of capillary numbers tested, and divides the Cal − Re diagram into stable and unstable regimes. Our findings offer insights into the behavior of bubbles in microfluidic applications, with implications for heat transfer, mass transfer, and cleaning processes in microchannels.
A note on the thrust of airfoils
(Cambridge University Press, 2025-06-10) Gordillo Arias de Saavedra, José Manuel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Universidad de Sevilla. TEP103: Mecánica de Fluidos
Here, we show that the thrust force of oscillating airfoils calculated within the linearised potential ﬂow approach by means of the vortex impulse theory coincides with the one resulting from the integration of the unsteady pressure distribution around the solid obtained by Garrick (1936) when the vertical component of the wake velocity is calculated self-consistently and the analysis retains the contribution of the ﬂux of horizontal momentum induced by the starting vortex. The limitations of the self-consistent linearised potential ﬂow approach for predicting the thrust force of airfoils oscillating periodically with small amplitudes but large values of the reduced frequency are also discussed, as well as the reasons behind the ability of other results in the literature to approximate measurements better than Garrick’s theory. In fact, for those cases in which the airfoil oscillates periodically, the ﬂux of horizontal momentum induced by the starting vortex is negligible and the vortices in the wake are convected parallel to the free-stream velocity, we have deduced an equation for the mean thrust coefﬁcient which differs from previously published results and is in agreement with experimental and numerical results. In addition, for those cases in which the airfoil is suddenly set into motion, we have also deduced an equation that retains the effect of the starting vortex and correctly quantiﬁes the transient thrust force.
Transient bubble rising in the presence of a surfactant at very low concentrations
(Elsevier, 2025) Fernández Martínez, Daniel; Cabezas, M. G.; López-Herrera Sánchez, José María; Herrada Gutiérrez, Miguel Ángel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España
We study the formation of the dynamic adsorption layer when a bubble is released in a tank containing water with a tiny amount of surfactant. The influence of the sorption kinetic constants is examined by comparing the experiments with Sodium Dodecyl Sulfate (SDS) and Triton X-100. The experiments allowed us to determine the parameter conditions that lead to a stable bubble rising and to validate the simulation. A simple scaling analysis and the simulation show that the formation of the dynamic adsorption layer can be split into three phases characterized by disparate time scales. The mechanisms controlling those phases are surfactant convection, adsorption–desorption, and diffusion. The amount of surfactant adsorbed onto the interface increases monotonously throughout the three phases. The experiments and the simulation show that the rising velocity reaches a maximum at times of the order of Kd-1( Kd is the desorption constant) when the dynamic adsorption layer is practically formed. This occurs even when only traces of surfactant are present in the liquid. The non-monotonous behavior of the maximum surfactant surface concentration is explained in terms of the reverse flow in the rear of the bubble right after the bubble release. This work contributes to the understanding of the complex interplay between hydrodynamics and surfactant transport and kinetics over bubble rising.
Integrating “nature” in the water-energy-food Nexus: Current perspectives and future directions
(Elsevier, 2025-02) Lucca, Enrico; Kofinas, Dimitris; Avellán, Tamara; Kleemann , Janina; Mooren, Caro E.; Blicharska, Margorzata; Pineda-Martos, Rocío; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; European Union (UE). H2020
Integrated approaches for managing natural resources are said to meet increasing demand for water, energy, and food, while maintaining the integrity of ecosystems, and ensuring equitable access to resources. The Water-Energy-Food (WEF) Nexus has been proposed as a cross-sectoral approach to manage trade-offs and exploit synergies that arise among these sectors. Although not initially included as a component of the Nexus, the role of nature in sustaining the water, energy, and food sectors and in regulating their interrelationships is increasingly recognised by Nexus researchers and practitioners. To converge existing approaches that integrate nature into the WEF Nexus and suggest a common framework, we – an interdisciplinary group of natural resources management researchers and systems thinkers from the European research network NEXUSNET COST Action – followed a collaborative process of knowledge creation combining literature review, elicitation of expert opinion and collaborative writing. Our results reveal a multiplicity of concepts utilised in the literature to represent, partially or fully, “nature” in the Nexus, such as “environment”, “ecosystems”, “ecosystem services”, “social-ecological systems”, and “biodiversity”. Disparity was also found in the role attributed to nature, represented by three key paradigms: (1) ecosystems as the fourth component of an expanded Nexus, i.e., the WEF-Ecosystems (WEFE) Nexus; (2) ecosystems as a foundational layer to the Nexus; and (3) the WEF Nexus as a central component of social-ecological systems (SES). By creating a hybrid approach that brings together the benefits of the respective paradigms, we present a forward-looking WEFE Nexus conceptualisation. This paradigm expands the mutual interlinkages among water, energy and food to the entirety of SES, thus acknowledging the social-ecological processes that are affected by and affect the WEF Nexus. The results of this collaborative research effort intend to provide researchers and stakeholders with means to better understand and ultimately manage Nexus issues towards a transformative change.
When does the elastic regime begin in viscoelastic pinch-off?
(Cambridge University Press, 2025) Gaillard, Antoine; Herrada Gutiérrez, Miguel Ángel; Deblais, Antoine; Van Poelgeest C.; Laruelle, L.; Eggers, Jens G.; Bonn, Daniel; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Economia, Industria y Competitividad (MINECO). España
In this experimental and numerical study, we revisit the question of the onset of the elastic regime in viscoelastic pinch-off. This is relevant to all modern filament thinning techniques, which aim to measure the extensional properties of low-viscosity polymer solutions. Examples are the slow retraction method (SRM) for capillary breakup extensional rheometry (CaBER), or the dripping method, in which a drop detaches from a nozzle. As part of these techniques, a stable liquid bridge is brought slowly to its stability threshold, where capillary-driven thinning starts. This thinning slows down dramatically at a critical radius, marking the onset of the elasto-capillary regime, characterised by a filament of nearly uniform radius. While a theoretical scaling exists for this transition in the case of the classical step-strain CaBER protocol, where polymer chains stretch without relaxing during the fast plate separation, we show that this theory is not necessarily valid for a slow protocol such as the SRM. In that case, polymer chains start stretching (beyond their equilibrium coiled configuration) only when the bridge thinning rate becomes comparable to the inverse of their relaxation time. We derive a universal scaling for, valid for both low- and high-viscosity polymer solutions. This scaling is validated by CaBER experiments with a slow plate separation protocol using different polymer solutions, plate diameters and sample volumes, as well as by numerical simulations using the FENE-P model.
Consumers’ knowledge, attitudes and willingness to pay for aquaponic products in Spain and Latin America
(Elsevier, 2021) Suárez Cáceres, Gina Patricia; Fernández Cabanás, Víctor Manuel; Lobillo Eguíbar, José; Pérez Urrestarazu, Luis; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Aquaponics is a productive system in which the production of vegetables and fish is synergistically combined within a circular economy framework. Although these systems have been in development for more than 50 years, the presence of aquaponic products in the markets is still very limited. Previous studies have been carried out trying to characterise consumers, although none was focused on Spain and Latin America. In this work, 636 responses have been obtained to a survey with 27 questions, which has enabled characterising the preferences of potential consumers and their willingness to pay higher prices for aquaponic products. Nearly 60% of the respondents knew what aquaponic was and this knowledge was influenced by the academic level and the concern for the environment. Most participants considered aquaponics as a very interesting food production system. They were mainly motivated to consume aquaponic products due to their quality and taste and to the absence of pesticides or chemical residues. A remarkable influence of the household income, concern for the environment and, mostly, prior knowledge about aquaponics was found concerning the willingness to pay higher prices. Therefore, advertising campaigns providing specific information on this type of food production would be advisable to increase its degree of acceptance.
Advances in urban horticulture by means of family-sized aquaponic systems: technical and social aspects
(International Society for Horticultural Science, 2022) Fernández Cabanás, Víctor Manuel; Pérez Urrestarazu, Luis; Suárez Cáceres, Gina Patricia; Fernández Cañero, Rafael; Lobillo, J.; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
Aquaponics is the combination of aquaculture and hydroponics, where fish effluents are used as nutritive solution by plants. At the University of Seville, different works have been developed over the last 12 years in order to improve the designs proposed by FAO, determine the safety of the food produced, study the productivity and profitability under Mediterranean climate, as well as the suppressiveness against some water-borne plant diseases. However, one of the most interesting findings that have stood out in the results are those related to social issues. The city of Seville has one of the neighbourhoods with the worst rates of social exclusion in Europe: El Polígono Sur, where different knowledge transfer activities have been developed. The objective of this work is to describe the aquaponic technology transfer activities to this disadvantaged neighbourhood and the social advances that were achieved during this period of collaboration, introducing healthy diet drivers and empowering adults in the neighbourhood. To achieve this goal, students participated in data collection operations (water quality, plant and fish production, etc.) and adults were teachers in a course. At the high school Joaquín Romero Murube, participating students received an extra supply of fresh vegetables while they practiced different curricular subjects in their aquaponic facilities, improving the nutritional quality of the students' diet, reducing absenteeism and promoting their learning in science, technology, engineering and mathematics (STEM subjects). Therefore, aquaponics has been a valuable tool to improve the nutritional quality of the students' diet, motivating their participation in academic activities and empowering the adults who taught the training courses in the University of Seville.
Improving the water quality of a pond coupled with a vertical garden. Case study: ornamental symbiosis
(International Society for Horticultural Science, 2023) Martínez Millán, l.; Suárez Cáceres, Gina Patricia; Fernández Cañero, Rafael; Rossini Oliva, Sabina; Fernández Cabanás, Víctor Manuel; Pérez Urrestarazu, Luis; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
In cities, space is becoming increasingly scarce to establish new green areas. Therefore, vertical greening systems are a promising solution, due to their multiple benefits. Among them is the ability of vegetation to reduce air and water contamination (phytoremediation). The objective of this case study was to evaluate the performance of a vertical garden coupled to a small ornamental pond functioning as an aquaponic system. The vertical garden was composed by felt modules and planted with different plant species: Chlorophytum comosum (Thunb.) Jacques, Fatsia japonica (Thunberg) Decne. & Planch., Ficus pumila L., Hedera helix L., Philodendron hederaceum (Jacq.) Schott, Tradescantia pallida (Rose) D.R. Hunt and Tradescantia zebrina (Bosse). It was connected to an ornamental pond with Carassius auratus (Goldfish) through underground pipes that recirculated the water between both subsystems. An autonomous functioning of the system was observed, with a satisfactory development of plants and an improvement in the pond appearance, which was confirmed by the presence of other species: birds, frogs, and tadpoles (bio-indicators of water quality). The results showed that the connection between a vertical garden and a pond induces an ornamental symbiosis, by saving the use of water and fertilizers (taking advantage of the nutrients provided by the fish feces and food scraps), while improving the quality of the water returning to the pond, which is necessary for the wellbeing of fish.
A fast numerical algorithm for finding all real solutions to a system of N nonlinear equations in a finite domain
(Springer, 2024) Chueca Díez, Fernando; Gañán-Calvo, Alfonso M.; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla. TEP219: Física de Fluidos y Microfluídica
A highly recurrent traditional bottleneck in applied mathematics, for which the most popular codes (Mathematica, Matlab, and Python as examples) do not offer a solution, is to find all the real solutions of a system of n nonlinear equations in a certain finite domain of the n-dimensional space of variables. We present two similar algorithms of minimum length and computational weight to solve this problem, in which one resembles a graphical tool of edge detection in an image extended to n dimensions. To do this, we discretize the n-dimensional space sector in which the solutions are sought. Once the discretized hypersurfaces (edges) defined by each nonlinear equation of the n-dimensional system have been identified in a single, simultaneous step, the coincidence of the hypersurfaces in each n-dimensional tile or cell containing at least one solution marks the approximate locations of all the hyperpoints that constitute the solutions. This makes the final Newton-Raphson step rapidly convergent to all the existent solutions in the predefined space sector with the desired degree of accuracy.
Evaluation of rooting and growth of pitaya (Hylocereus spp.) cuttings in soilless production: comparison of hydroponic vs. aquaponic systems
(Taylor & Francis, 2024) Suárez Cáceres, Gina Patricia; Malia Torrejón, Miguel; Pérez Urrestarazu, Luis; Gross, Jackson A.; Fernández Cabanás, Víctor Manuel; Universidad de Sevilla. Departamento de Agronomía; Universidad de Sevilla. Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos
effluents generated in aquaculture could contribute to increased risk of environmental contamination. aquaponic could facilitate the resolution of this problem by transforming those potential pollutants into nutrients for plants, providing an extra vegetable production in a circular economy framework. highly profitable vegetables such as pitaya (Hylocereus spp.) could improve the economic viability of these farms, but little is known about its performance in aquaponic systems. rooting and vegetative growth of 12 cuttings of white-fleshed pitaya (Hylocereus undatus) and red-fleshed pitaya (Hylocereus hybridum) were evaluated over a period of six months in two aquaponic systems rearing tilapia with different hydroponic subsystems (nutrient Film technique, nFt and Media Bed, MB). a control group of hydroponic culture using substrate filled pots was used for comparison. Water quality and environmental parameters were also measured to evaluate their influence on plant development. Hylocereus hybridum showed higher vegetative growth, and earlier shoot emission in combination with the control system, followed by the nFt and finally the MB. in relation to root growth, Hylocereus undatus showed best results in combination with the substrate system. Best results for precocity in root emission, evaluated in the nFt system, were obtained for Hylocereus hybridum. Water quality parameters had no significant effect on plant development, while fish live weight increased in both systems.

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