Opposite Wall Research Articles

Film Effectiveness Downstream the Trenches with Tilted Target Wall

Film cooling is a commonly-accepted effective way to protect the gas turbine hot sections from the high temperature products of the combustion chamber. Numerous film hole geometries have been the subject of investigation by many researchers over the past three decades with the aim of keeping the target wall under the maximum allowable temperature with the least amount of precious cooling air and minimum aerodynamic losses. In this study, we are proposing a new trench geometry that is fed by 30°-inclined embedded circular film holes entering from the trench sidewall. The cooling jets impinge on the opposite wall of the trench which is tilted towards the jets and then is pushed over the coverage wall by the main flow. Three trench geometries with the same exit area and tilt angles (the angle between the trench side- and top-wall) of 75°, 90°, and 105° degrees are tested for three blowing ratios of 0.5, 0.75, and 1.0, and the film effectiveness results are compared using the adiabatic pressure sensitive paint technique. CFD analyses are also performed using the realizable <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>k</mi> <mo>−</mo> <mi>ε</mi> </math> turbulence model with the enhanced wall function option. Major conclusions of this study were that the trench geometry with the trench tilt angle of 75°, corresponding to the smallest trench volume, had the best performance at the lowest blowing ratio, and good agreement was observed between the CFD and test results.

“String-to-ring” traction technique for endoscopic submocosal dissection in the treatment of rectal tumors

The results for “string-to-ring” ESD and conventional ESD were compared in present study. The “string-to-ring” method was developed to create traction using a thread, fixed to the edge of the tumor, that is moved through a ring, located on the clip on the opposite wall. The study included 41 ESDs of the lesions larger than 3 cm in the rectum, that were performed from October 2016 to June 2021. Patients were divided into two groups (“string-to-ring” ESD, n = 19; conventional ESD, n = 22). Time of the procedure and the frequency of complications were evaluated. Analyzing the obtained data, the “string-to-ring” method allowed to shorten the operation time (from 85,8 ± 17,5 to 63,6 ± 15,3 min), reduce the rate of intraoperative bleeding and perforations from 19% to 0%. At the conclusion, ESD with “string-to-ring” traction—a promising technique with potential for clinical application. The advantage of this method provide better visualizing the submucosal layer due to the direction of gravity. This method facilitates ESD, reduces procedure time and the number of intraoperative complications—bleeding and perforation.

S2529 Threading the Needle: Safely Removing Double-Edged Sharp Foreign Bodies

Introduction: Foreign body ingestion is a common phenomenon among individuals with psychiatric disorders, alcohol intoxication, developmental delay, or in incarcerated individuals. Most ingested foreign bodies pass spontaneously without complication but 10-20% require endoscopic intervention. Impaction, perforation, or obstruction often occurs at angulations or narrowing. Early recognition and urgent upper endoscopy (EGD) for foreign body removal may improve clinical outcomes. Here we present a case of melena and abdominal pain secondary to foreign body ingestion. Case Description/Methods: An 83-year-old male with a past medical history of pulmonary embolism on warfarin, alcohol use disorder, and anxiety presented after 2 black, tarry stools and light-headedness. On admission his vitals were stable and labs were notable for an International normalized ratio (INR) of 3.3 and a Hemoglobin (Hgb) of 12.3g/dL. He was treated with Vitamin K and intravenous pantoprazole twice daily. The next day his Hgb was found to be 8.2g/dL and an EGD was performed revealing antral ulcerations and a 3.5cm sewing needle and thread with both ends penetrating opposite walls of the antrum (Figure A, B). Multiple attempts at removing the needle with rat tooth and jumbo forceps were unsuccessful and the procedure was aborted. Follow up computed tomography imaging did not reveal perigastric fluid or pneumoperitoneum post-procedurally. On hospital day 3 a repeat EGD was attempted and showed the needle was only perforating mucosa along one side of the gastric body; it was able to be removed via overtube and raptor device (Figure C). Discussion: Endoscopic removal of sharp ingested foreign bodies can prove to be challenging. Several risk factors including age and duration of impaction are associated with adverse events, such as laceration, perforation, and ulcers. Double pointed/sharp objects are particularly challenging given they are harder to grasp and maneuver. That, in addition to luminal contractions, likely contributed to the difficulty retrieving the needle in this case despite using recommended tools. Had the second endoscopic retrieval attempt failed, the patient would have required surgical evaluation. Overall, the benefit of further endoscopic retrieval attempts versus the risk of perforation from the foreign body or complications from the procedure itself must be weighed case by case.Figure 1.: Endoscopic Evaluation of Patient with Foreign Body A – Foreign body wedged between opposite ends of pylorus (Highlighted by top arrow) B – Full view of sewing needle with thread in gastric antrum C – Sewing needle after removal.

Free convection of temperature-dependent thermal conductivity based ethylene glycol-Al2O3 nanofluid in an open cavity with wall heat flux

The natural or free convection flow in an open cavity filled with ethylene glycol-Al2O3 nanofluid has been integrated numerically using the multiple-relaxation-time (MRT) lattice Boltzmann method (LBM) with the Graphics Process Unit (GPU) acceleration. The applications of this type of problem frequently appear in open-door ovens and refrigerators and in the cavities of central solar receptors. The ceiling and bottom walls of the cavity are thermally adiabatic. The right side of the cavity is fully opened while heat flux condition is imposed on its opposite wall. The thermal conductivity of the nanofluid varies with fluid temperature. Numerical simulations have been conducted for a fixed Prandtl number, Pr=16.6, with varying other controlling parameters, i.e., the Rayleigh number from Ra=105 to 107, and nanoparticle volume fraction from 0 to 5%. The streamlines, isotherms, mid-line temperature and velocity distributions, and the rate of heat transfer regarding the Nusselt number have been presented in this article. The isolines and tabular form give the local and total entropy generation due to the fluid friction and temperature gradients. The tangential and normal velocity components grow dramatically as Ra increases; however, the temperature diminishes with Ra. Also, the locally distributed Nusselt number increases in magnitude with nanofluids’ volume fraction and Rayleigh number. The total entropy enhances significantly for the augmentation of the nanoparticles volume fraction, and the entropy due to fluid friction dominates over the entropy generated by the temperature gradients.

Triggering Shock Wave Positions by Patterned Energy Deposition

The problem considered in this work is shock wave (SW) positioning control in shock-dominated flows. Experiments are conducted to investigate the triggering effect of patterned near-surface electrical discharges on SW reflection from plane walls. In the wind tunnel, M=4, P0 = 4 bar, a solid wedge SW generator is mounted on the upper wall. Q-DC filamentary electrical discharges were arranged on the opposite wall, so that the SW from the wedge impinged on the plasma filaments that are arranged flow-wise in either a row of three or a single central filament. Within the supersonic flow, narrow subsonic areas are actuated by electrical discharge thermal deposition, resulting in pressure redistribution, which, in turn, relocates the reflection of impinging SW to a predefined position. Mie scattering, schlieren imaging, and wall pressure measurements are used to explore the details of plasma-SW interaction. Using Mie scattering, the three-dimensional shape of the SW structure is mapped both before and after electrical discharge activation. Plasma-based triggering mechanisms are described in terms of the physical principles of flow control and a criterion for determining the effectiveness of the flowfield control.

Theoretical analysis of electrical double layer effects on the multiphase flow of Jeffrey fluid through a divergent channel with lubricated walls

A theoretical study of two-phase non-Newtonian fluid with heat transfer is presented in this article. Jeffrey fluid model is used as the base liquid to form a multiphase suspension with the help of gold particles. Heating effects have also been applied on an electro-osmotic two-phase flow through a divergent channel. The lubrication effects have been applied to dampen the skin friction of the opposite walls. An analytical solution is obtained for the nonlinear multiphase fluid flow with heat transfer. Separate expressions for the volumetric flow rate of two-phase flow and pressure gradient are determined via a complex mathematical manipulation. A concise parametric study reveals that slippery walls of the channel have a prominent influence on the momentum of both phases.

Insight into the Structure and Dynamics of Ethanol-Water Binary Mixture Confined in Nanochannel by Mica and Graphene.

Investigation of the structural properties and dynamics of fluid mixture confined in nanochannels has become an essential topic in many fields due to potential applications in nanofluidic devices and biological systems. Here, we study the ethanol-water blend confined between the mica and single or multilayer graphene for different slit pore widths, ethanol content, and temperatures. Our molecular dynamics simulation indicates that water molecules are adsorbed at the mica surface, while ethanol molecules prefer to be adsorbed near the graphene surface. We find that distinct layers of ethanol molecules form as the channel width and ethanol content in the mixture are increased. The diffusion of confined ethanol and water molecules depends on the nanopore widths, concentrations, and temperatures. Interestingly, at nanopore widths of 1.0 and 1.3 nm, the mobility of confined ethanol molecules is greater than that of water molecules for all ethanol concentrations. In contrast, at pore width of 0.7 nm, the opposite behavior is observed at lower concentrations of ethanol (xEtOH = 0.1 and 0.3) in the mixture. Furthermore, the diffusivity of ethanol and water in the mixtures increases with increasing the temperatures. The hydrogen bond and cluster analysis imply the segregation of water molecules near the mica surface, while ethanol molecules are near the opposite pore wall (graphene).

Implementation of an Integrated Dielectrophoretic and Magnetophoretic Microfluidic Chip for CTC Isolation.

Identification of circulating tumor cells (CTCs) from a majority of various cell pools has been an appealing topic for diagnostic purposes. This study numerically demonstrates the isolation of CTCs from blood cells by the combination of dielectrophoresis and magnetophoresis in a microfluidic chip. Taking advantage of the label-free property, the separation of red blood cells, platelets, T cells, HT-29, and MDA-231 was conducted in the microchannel. By using the ferromagnet structure with double segments and a relatively shorter distance in between, a strong gradient of the magnetic field, i.e., sufficiently large MAP forces acting on the cells, can be generated, leading to a high separation resolution. In order to generate strong DEP forces, the non-uniform electric field gradient is induced by applying the electric voltage through the microchannel across a pair of asymmetric orifices, i.e., a small orifice and a large orifice on the opposite wall of the channel sides. The distribution of the gradient of the magnetic field near the edge of ferromagnet segments, the gradient of the non-uniform electric field in the vicinity of the asymmetric orifices, and the flow field were investigated. In this numerical simulation, the effects of the ferromagnet structure on the magnetic field, the flow rate, as well as the strength of the electric field on their combined magnetophoretic and dielectrophoretic behaviors and trajectories are systemically studied. The simulation results demonstrate the potential of both property- and size-based cell isolation in the microfluidic device by implementing magnetophoresis and dielectrophoresis.

The Price

The Price

Experimental study on cyclic behavior of thread-fixed one-side bolts bolted endplate connection to strengthened concrete filled square steel tube with fixed thread length

This paper presented the experimental results of the Endplate Connection to Concrete Filled square Steel Tube (ECCFST) with fixed thread length via Thread-fixed One-side Bolts (TOBs) under cyclic loading. Two stiffening strategies, namely the internal polygonal tube stiffener and the cross-H section stiffener, with two stiffener flange thicknesses (18 mm and 14 mm) corresponding to two column wall thicknesses (6 mm and 10 mm), respectively, were proposed to strengthen the panel zone of the connections. Failure modes occurring for the connections were mainly affected by the weakest component of the joint region. Besides, the moment-rotation hysteretic curves and seismic performance of the joints were compared and analyzed. For all cases with fixed thread anchored length, the TOBs performed well and no thread failure occurred under the repeated reversal loading. Test results revealed that the mechanical performance of the joints can be ameliorated by adopting the strengthening components especially the cross-H section stiffener, which effectively limited the tube wall deformation from transferring the force to the opposite tube wall through the web of the stiffener. The rotation capacity and ductility of ECCFSTs were satisfactory and can meet the ductility limitation with regard to FEMA-350, demonstrating a potential for ECCFSTs in practical application.

Seismic behavior of TOBs bolted endplate connection to strengthened CFST column

When using the Thread-anchored One-side Bolts (TOBs) which are a type of one-side bolts anchored through the tube wall hole threads instead of the nuts, the conventional Concrete Filled square Steel Tube (CFST) with the limited wall thickness fails to provide the sufficient thread anchored length to resist the tensile force of TOBs. Meanwhile, the joint region of the relatively thin tube wall is prone to deform outward to a large degree, which is crucial to the safety of the whole structure. To solve the above issues, in this work an experimental investigation on TOBs bolted Endplate Connection to strengthened CFST (TOBEC-CFST) under cyclic loads is conducted by putting a stiffener inside the CFST. Six specimens were designed to study the effects of following parameters: (a) stiffener type (the inner polygonal tube stiffener or the cross-H section stiffener); (b) thread anchored length (18 mm and 24 mm); and (c) bolt diameter (M16, M20 and M22). The experimental results revealed that the hole thread fracture can be avoided by increasing the stiffener flange thickness to extend the hole thread length and the inner stiffener can improve the behavior of the panel zone of the connection. Compared to the inner polygonal tube stiffener, the cross-H section stiffener can effectively enhance the overall integrity of the connection because of the presence of the web transferring force directly to the opposite tube wall, contributing to a higher bearing capacity and energy dissipation capacity of the joints. Increasing the bolt diameter can improve the bearing capacity and energy dissipation capacity of TOBEC-CFSTs, but the degree of the improvement does not increase linearly with bolt diameter. Based on test results, to enhance the overall mechanical behavior of TOBEC-CFSTs in seismic zones, the cross-H section stiffener is recommended provided for sufficient thread length.

Archiving the Algerian Revolution in Zineb Sedira's Gardiennes d'images

Archiving the Algerian Revolution in Zineb Sedira's <i>Gardiennes d'images</i>

Applicability evaluation of the ultrasonic pulse-train Doppler method on the disturbed flow in a pipe

This manuscript presents an experimental study to evaluate the applicability of the ultrasonic pulse-train Doppler method (UPTD) to the disturbed flow in a pipe. The UPTD can expand the detectable velocity range compared with the conventional ultrasonic pulse Doppler method and has an advantage of trouble-free installation into conventional hardware. Comparative experiments were conducted using two different transducer frequencies, 1 MHz and 4 MHz. The UPTD was only applied to the 4-MHz condition to expand the velocity range fourfold, which is equal to the velocity range of a 1-MHz transducer. The probability density distributions of the measured velocities were almost the same between 1 MHz and 4 MHz, even though the measurement position was not only downstream of a long straight pipe but also downstream 10 or 5 pipe diameters from an obstacle plate. To estimate the influence of aliasing on the velocity measurement for a large fluctuating flow, experiments using a 2-MHz transducer were also conducted. These results indicated that it is possible to estimate the standard deviation of the velocities measured under the aliasing condition, and the accuracy of flow rate measurement decreases when the standard deviation of the velocity exceeds the measurable velocity by approximately twice. Additionally, the flow rate by the 1-MHz transducer was about −2% smaller than that by the 4-MHz transducer for both the straight pipe and disturbed conditions. Through the validation of the influence of the measurement volume between 1 MHz and 4 MHz conditions, the flow rate difference was found to be likely due to the influences of not only the measurement volume but also the standing wave formed by the pulses reflected on the opposite pipe wall.

Experimental investigation and reduced-order modeling of plasma jets in a turbulent boundary layer for skin-friction drag reduction

Stereo particle imaging velocimetry measurements and reduced-order modeling are combined to provide a full picture of the interaction of plasma jets with a turbulent boundary layer (TBL). Three working modes of the plasma actuator are investigated, corresponding to a unidirectional jet (mode A), a steady crashing jet (mode B), and a spanwise oscillating jet (mode C). The results show that in mode C, a periodical alteration of two opposite wall jets can only be achieved at a low modulation frequency of 20 Hz. As the frequency increases to 100 Hz, the two unsteady wall jets collide in the middle, producing a meandering vertical jet column. In the cross-flow TBL, mode A induces a single streamwise vortex, which grows in size within the plasma actuation zone and decays rapidly in strength after propagating beyond. As a comparison, modes B and C produce a counter-rotating vortex pair during the interaction. The skin-friction drag variations within the plasma actuation zone are dominated by the cross-stream momentum transportation of streamwise vortices. In the vortex upwash zone where a strong shear is present, high levels of turbulent kinetic energy are produced. Physically, the spanwise shaking and vertical jumping of plasma jet heads contribute noticeably to turbulent fluctuation. Experimental evidence supports the simplification of a streamwise momentum equation into a nonlinear transportation–diffusion equation, resulting in a reduced-order streamwise vortex transportation model. Detailed comparison with the experimental data shows that this model is able to give a reasonable prediction of the cross-stream flow patterns and streamwise velocity variations within minutes.

Comparison between sonic jets with one jet orifice and two opposite orifices into a Ma-3.0 supersonic crossflow through circular ducts

Large-eddy simulations and nanoparticle-based planar laser scattering experiments are conducted to investigate various physical aspects of transverse sonic jets injected into a Ma-3.0 supersonic crossflow through a circular pipe. Configurations with one jet and two opposite jets are compared. For the single jet, a separation shock is generated by the recirculation zone on the opposite wall, and this intersects with the jet shear layer to push several jet plumes into the near-wall region. For the two jets, the bow shocks interact with each other, forming an oblique shock train. All of the shocks promote vortex breakage in jet wakes. A counter-rotating vortex pair is generated in the jet near-field region, enhancing the local mixing. A near-wall region in the jet lee between the counter-rotating vortex pair branches exhibits a low fuel mass fraction. The jet fluid in the downstream near-wall region is entrained by the crossflow upstream of the jet. The interaction between the bow shocks and shear layers of the two jets induces recirculation zones in the lee of the jet, which enhance the fuel mixing. This explains the phenomenon whereby the total pressure recovery coefficient and mixing efficiency of two jets are higher than those of the single jet.

Tethers: A Traveler's Ode to Book Swaps, Big and Small

TethersA Traveler's Ode to Book Swaps, Big and Small SarahBelle Selig (bio) Click for larger view View full resolution A frequent traveler currently winding her way through Central America celebrates the free book swaps along the way, and all the hope and longing nestled amongst their shelves. I'll speak of cathedrals. Of sandwiches and cobblestone, of midnights spent in hot springs and the red sands of the Namib slipping through my fingers. When I return home at last, I will remember most strongly the moments of discovery, of catharsis, of flavor, and share them too often with exasperated loved ones. I will not speak of the books that I read along the way, though they filled the crevices of my days. And least of which will I speak of the bookshelves I found them on, the dusty book swaps in hostel common areas and corner cafés that I frequented, though they too were moments of discovery and catharsis. I will forget them, in time, as they quietly fade to make space for more cathedrals, more natural wonders. But these shelves do not mind the forgetting. Give, take: that is all they ask. [End Page 34] For the perennial traveler, a book swap is more than a minute of respite from the babel outdoors, a freebie when the last of one's coins have been spent on a museum ticket, a street snack, shampoo. A book swap is a new town without a map; a treasure hunt for the sword-shy. If I have the afternoon to linger, a book swap is window shopping the streets of Oaxaca, or selecting the perfect flavor of gelato on a hot day. If I've a bus to catch, or a hangover nestled between my brows, it is frustrating and terribly high-stakes: a fillet knife sliding down the delicate spine of a mackerel. On these shelves, there is no pecking order. Here gathers a ménage of authors who would, in your typical bookstore, live on opposite walls, split by genre and popularity, by surname and sales price. Much like the way I share this cramped dorm room with travelers from South Korea, Argentina, Australia, Trinidad and Tobago; that most private space, shared for one night with people of different languages and histories who would otherwise live a world apart, a single point of contact before we scatter across continents. I imagine the evenings, if these authors whisper to one another like we do, two strange soirées swapping gossip in the dark. Far from the hands of booksellers and publicists, a book swap is a step back in time, before best-seller lists and starred reviews, before book banners flashing bright in our webpage margins. It does not matter who designed the cover or endorsed it on Twitter or how many awards it won. For those of us mad enough to be authors by trade, this is an encouraging thought. It is the book business distilled to its purest form: a writer writes a story, a reader reads it. It is a chance for us—not for sales, nor recognition; the units on our P&Ls will not change—but to finally realize that old dream, to be on the other side of that blessed communion when a young reader finds herself in an author's words and for a moment stops feeling so scared. A book swap is a balm for loneliness. It is here at this altar that two dozen hands from two dozen countries have all left an offering. Because that is what it is, to leave a book for another to find: an offering of oneself, a small fraction of one's hope and longing left like breadcrumbs in the dirt. And when I place my book just so, with a secret kiss to its cover—in that perfect vacancy that book swaps always seem to have, as if they are waiting for just this book to arrive—I imagine the person who will find it, and we are tethered, that reader and I, though we will never know the sound of each other's laughter. We are tethered to each other and to...

A Two-Stage EHD Gas Pump in a Square Channel With Electrodes Mounted on Two Opposite Facing Walls

This article explores ways to further improve the performance of an electrohydrodynamic (EHD) gas pump operating in a square channel. To this end, the present pump uses electrode assemblies that are grouped in two and are mounted on the two opposite walls facing each other. The emitting electrodes are flush mounted on the channel walls so that the air flow produced is similar to that of a wall jet. The electrode configuration with three emitting electrodes on each wall is investigated for its effectiveness in enhancing the volume flow rate as well as reducing the power requirement. The results obtained are compared with those reported in the previous studies with various electrode configurations to determine which performs the best. Through the performance assessment of various pump designs, the present results have provided important information for practical applications of EHD technology.

A Numerical Study of the Effect of Rectangular Shaped Ribs Organized in Different Patterns on the Thermal Performance of a Solar Air Heater

Abstracts: A solar air heater is a useful device that can be used to raise the temperature of a roomby capturing heat from solar energy This paper is about a two-dimensional numerical study that was done to predict the influence of transverse rectangular cross-sectioned ribs on the convective heat transfer properties of a solar air heater. It is a rectangular duct with an absorber plate on top, and heat only falls on the top of the absorber plate. The thermal performance of air flowing through the rectangular duct is significantly altered when different shapes and orientations of ribs/baffles are introduced just beneath the absorber plate. A comparison was made between the results of thin (high aspect ratio) and square ribs arranged in three patterns, namely, single wall arrangement ,staggered arrangement and in-line arrangement on two opposite walls. The Nusselt number variation with Reynolds number range 4000-25000 was checked at a fixed rib pitch (p) and height (e) values. Computational fluid dynamics (CFD) simulations were performed using commercially available software ANSYS FLUENT v15.0..The results revealed that the thin ribs yielded better performance than the squared ones. Out of the three arrangements, the best thermal performance was given by thin inline ribs whose convective heat transfer coefficient was 1.93 times smooth duct’s convective heat transfer coefficient.

Improvement of spectroscopic method for determining refractive index of filament sample material for 3D printing in terahertz range

The article considers the topical problem of non-destructive filament defectoscopy for 3D printing. The subject of the research is the process of determining the refractive index of the filament material for 3D printing taking into account the reflections from sample opposite walls, which is studied by terahertz spectroscopy in the time domain. Reflections from opposite walls are called the Fabry-Perot effect, and interference members resulting from reflections from walls are traditionally taken into account by summation and represented as a series. The disadvantage of the model in the form of a simple summation is the rejection of the members of the series above the fourth, which leads to inaccuracies in the model. The main problem with terahertz spectroscopy and this study in particular is the contradiction between the rapid development of terahertz spectroscopy and the slow development of models used in terahertz spectroscopy, while the adjacent microwave region has a set of ready-made models. Models based on the description of a standing wave in the microwave tract with refinements, transferred to a new region of terahertz spectroscopy in the time domain. The scientific novelty lies in increasing accuracy by taking into account previously unaccounted for interference members. The analogy between the Fabry-Perot effect used in terahertz spectroscopy and the reflections in a microwave multiprobe multimeter suggested the following recommendations. First, because the phase distance between the sensors in the microwave multimeter is similar to the thickness of the sample in terahertz spectroscopy, therefore, there was choosen such a sample thickness that the interference members are compensated, and secondly, instead of simple sum up it is possibility apply algorithmic processing, the condition for this is the existence in addition to the main signal in the time domain of the recorded echo signals of much smaller amplitude, therefore, one can build a system of equations and by solving it to determine the desired refractive index parameters of the filament sample material.

Consequences of interactions between stormwater infiltration systems, shallow groundwater and underground structures at the neighborhood scale

ABSTRACT This study investigates the interplay between stormwater infiltration devices, shallow groundwater and underground structures (sewer pipes and building foundations) at the neighborhood scale. Considering a hypothetical urban area, different scenarios are designed by varying the underground components taken into account within two soil types. For the least permeable soil, interactions with groundwater reduce the infiltration within devices (−99 to −151 mm/y) and increase the transpiration in surrounding areas (+42 to +50 mm/y). For both soils, the overall water table rise due to infiltration and mounding beneath infiltration devices increases groundwater drainage by sewer pipes and draining systems (+7 to +96 mm/y) and the water elevation differential between opposite walls of impervious structures (up to +1.5 m). In turn, underground structures strongly modify groundwater flow. For the least permeable soil, this directly affects groundwater influence on infiltration and transpiration and thus the overall effects of infiltration strategies at the neighborhood scale.