Asymmetric Pressure Distribution Research Articles

Capillarity Constructed Open Siphon for Sustainable Drainage.

Siphon is an effective method to transfer liquid from a higher to a lower level, which has many applications in hygienic design, clinical apparatus, and hydraulic engineering. Traditional operation requires energy to overcome gravity and establish flow in a closed system. Achieving sustainable high flux siphon drainage without energy input remains a challenge due to viscous dissipation. Here, an unexpected open siphon behavior on the South American pitcher plant Heliamphora minor consisting of trichomes covered pitcher and a wedge-shaped sheath is examined. Exploiting the concept of Digital Twin, a new biomimetic research method by transforming the biological sample to a virtual 3D model is proposed and unveiled that maintained connection of wicking on sub-millimeter long trichomes due to asymmetric pressure distribution and ascending in wedge sheath under unbalanced pressure forms continuous surface flow. Exploring this mechanism, a biomimetic siphon device achieving continuous high flux exposed to ambient air is constructed. Besides, particles floating on the meniscus in the outside wedge move under a curvature gradient as water ascends, which implies a biological nutrient capture method and new dust collection manner in the drainage system. Applying the underlying principle enhances the siphon efficiency of floor drains and has the potential for other liquid transfer device design improvements.

Analysis of Unsteady Internal Flow and Its Induced Structural Response in a Circulating Water Pump

As critical equipment in nuclear power systems, the stability of circulating water pumps (CWP) directly impacts the efficiency of power plants. To investigate the impact mechanisms of the unsteady flow characteristics and flow-induced forces on the rotation system, numerical simulation methods were employed to calculate the internal flow of a volute mixed-flow CWP under different flow rates (0.8Qd, 1.0Qd, 1.2Qd). The flow field results indicate that, under the part-load condition, the flow within the volute is chaotic with high energy losses, while under the over-load condition, there is a significant velocity gradient within the impeller, leading to relatively severe flow losses. Additionally, the rotor–stator interface is a major factor in flow-induced pulsations, and the asymmetric pressure distribution within the volute results in radial force imbalance. The finite element method (FEM) results indicate that the position of maximum stress on the pump shaft is closely related to the ratio of radial and axial force. Increasing the flow rate appropriately has been noted to be advantageous in reducing flow-induced forces and their amplitude, consequently diminishing the forces on the rotation system and improving the long-term operational stability of the CWP.

Dynamic characteristics and application of dual throat fluidic thrust vectoring nozzle

Thrust vectoring technology plays an important role in improving the maneuverability of aircraft. In order to overcome the disadvantages of mechanical thrust vectoring nozzles, such as complications of structure and significant increases in weight and cost, fluidic thrust vectoring nozzles are proposed. Dual Throat fluidic thrust vectoring Nozzle (DTN) has received wide attention due to its excellent thrust vectoring efficiency and minimal thrust loss. In this study, three-dimensional unsteady numerical simulations of a single axisymmetric DTN are conducted first to analyze its dynamic response. Then the pitch and yaw control characteristics of DTN equipped on a flying-wing aircraft are investigated. It is found that the dynamic response will experience three stages: rapid-deflecting stage, oscillating stage, and steady stage. A complete recirculation zone forms at the end of the rapid-deflecting stage, which pushes the primary flow to attach to the wall opposite the secondary injection. Meanwhile, the exhaust flow is deflected. In terms of DTN’s application, the DTN equipped on the flying-wing aircraft is capable of providing effective pitch and yaw moments at all angles of attack and Mach numbers. In addition, continuous pitch and yaw moments can be obtained by adjusting the secondary mass flow ratios. The control moment is generated due to the asymmetrical pressure distribution of nozzle surface, which is mainly contributed by the pressure decrease on the secondary injection surface. Moreover, the DTN equipped on the flying-wing aircraft has a relatively high thrust vectoring efficiency of around 5°/% and a thrust coefficient of around 0.95 when nozzle pressure ratio equals 4. These results provide an important theoretical basis for the practical application of DTN.

Laboratory study on mechanical behavior of hollow π-type steel–concrete composite support in loess tunnel

Failure or over-deformation of tunnel supports is common when tunneling in loess areas. Steel-concrete composite support (SCCS) is an innovative new support system that could provide a viable solution to improve the support in loess tunnels. Due to a lack of research, there is only a preliminary understanding of the structural effects of employing π-type SCCS arch as the initial load-bearing element. Based on similarity theory, we perform a large-scale ring model test to investigate the mechanical behavior of the π-type SCCS arch without grouting under typical surrounding loess pressure, i.e., symmetric and asymmetric bias pressure distributions. The damage patterns, deformation evolution, and structural strain development are obtained via the experimental investigation and presented in detail. The progressive failure and ultimate bearing capacity of the hollow π-type SCCS arch are further compared under a designed loading situation. It is concluded that the failure of the π-type SCCS arch has three stages, including the coordinate deformation stage, the load-bearing stage, and the failure stage, respectively. However, the deformation and failure modes under different surrounding pressure behave differently. The stiffness and bearing capacity of the π-type SCCS arch under symmetrical pressure is 1.65 and 1.16 times greater than that under asymmetric pressure, respectively. This experimental study provides new insights into the mechanical behavior of new arch frames for loess tunnel construction, which can serve as a benchmark for further theoretical and numerical studies.

Simultaneous hydrodynamic cavitation and nanosecond pulse discharge plasma enhanced by oxygen injection

A novel Hydrodynamic Cavitation-Assisted Oxygen Plasma (HCAOP) process, which employs a venturi tube and oxygen injection, has been developed for enhancing the production and utilization of hydroxyl radicals (·OH) in the degradation of organic pollutants. This study has systematically investigated the fluid characteristics and discharge properties of the gas–liquid two-phase body in the venturi tube. The hydraulic cavitation two-phase body discharge is initiated by the bridging of the cavitation cloud between the electrodes. The discharge mode transitions from diffuse to spark to corona as the oxygen flow rate increases. The spark discharge has the highest current and discharge energy. Excessive oxygen results in the change of the flow from bubbly to annular and a subsequent decrease in discharge energy. The effects of cavitation intensity, oxygen flow rate, and power polarity on discharge characteristics and ·OH production were evaluated using terephthalic acid as a fluorescent probe. It was found that injecting 3 standard liter per minute (SLPM) of oxygen increased the ·OH yield by 6 times with only 1.2 times increase in power, whereas<0.5 SLPM of oxygen did not improve the ·OH yield due to lower breakdown voltage. Negative polarity voltage increased the breakdown voltage and ·OH yield due to asymmetric density and pressure distribution in the throat tube. This polarity effect was explained by numerical simulation. Using indigo carmine (E132) as a model pollutant, the HCAOP process degraded 20 mg/L of dye in 5 L water within 2 min following a first-order reaction. The lowest electric energy per order (EEO) was 0.26 (kWh/m3/order). The HCAOP process is a highly efficient flow-type advanced oxidation process with potential industrial applications.

An approach of micro-slip modeling based on asymmetric contact pressure distribution and its application in nonlinear boundary beam system

A novel micro-slip friction modeling approach based on the Iwan model is presented here. The normal load and tangential stiffness are reassigned reasonably to obtain the tangential force–displacement expression, and the relationship between the asymmetry of contact pressure distribution and the Iwan density function is established. The micro-slip model depends on the distribution of contact pressure, and has the ability to degenerate into a macro-slip model. Based on the model, a simplified non-linear dynamics model of a rotating blade with a dovetail joint is developed, and its effectiveness is verified by comparing it with a relevant reference. The first-order bending vibration of the blade under distributed excitation is analyzed. The results indicate that the pressure distribution of the contact interface has a significant effect on the amplitude–frequency response of the blade and the contact behavior on the joint interface. Compared with the proposed micro-slip model, the single point contact model overestimates the response amplitude. The amplitude–frequency curve obtained by this model is obviously different from the macro-slip model. It is proved that the micro-slip model can more accurately simulate the nonlinear vibration characteristics of tenoned blades, which provides new insights for the study of the vibration characteristics of tenoned blades.

Nonlinear URANS model for path-following control problem towards autonomous marine navigation under wave conditions

An accurate prediction of the performance of maritime autonomous surface ships (MASS) to follow a predefined path in waves is of critical importance for ensuring safe autonomous marine navigation. Traditional methods for the study of path-following problems are based on simplified mathematical ship models and are incapable of precisely resolving the complicated interactions between the hull, propeller, rudder, and incident waves under path-following control. In the present study, a CFD-based dynamic model for path-following problems is developed for autonomous marine navigation by means of a fully nonlinear unsteady Reynolds-Averaged Navier-Stokes (RANS) solver combined with the Line-of-Sight (LOS) guidance law. Fortunately, an unsteady RANS solver is capable of incorporating viscous and turbulent effects and the free surface resolution critical to path-following problems, allowing a better prediction of a ship's path-following performance in waves. To obtain practical insight into the performance of the ship executing path-following control for autonomous navigation in waves, a comprehensive analysis of path-following tasks in waves covering the whole range of important wave directions and wave heights was carried out in this study. The numerical results demonstrated that when the ship performed the path-following manoeuvre under the beam and quartering seas, the greatest oscillatory deviation from the predefined path was observed due to the asymmetric pressure distribution on the ship hull caused by the incident waves. It was also confirmed that wave heights strongly affected the trajectories experienced by the ship performing the path-following task in the beam and oblique seas; the deviation from the predefined path was found to increase with the increase in the wave height. As high-performance computational resources become increasingly available, the proposed CFD method will provide an accurate and efficient way to predict the performance of autonomous surface ships performing path-following tasks in waves, providing a valuable contribution to enhancing the safety of autonomous marine navigation.

Design and Analysis of a New Pressure Relief Valve for Oil-Immersed Electrical Equipment

Abstract Internal arcing in oil-immersed electrical equipment is inevitable and of great danger. Transient overpressure should be released by protectors quickly and controllably. Currently available pressure relief valves cannot fully protect the electrical equipment due to mismatch between insufficient relief capacity with correspondingly weak valve structure and increasing arcing energy in upgrading electrical systems. Additionally, flaming possibility of ejected high-temperature oil–gas mixture is distinct, and retained oil in an oil tank without any isolation may be ignited by the flame. Unfortunately, resealing of some existing single-outlet valves is out of control due to asymmetrical hydraulic pressure distribution on the valve plate which causes unstable valve plate movement. Therefore, a new pressure relief valve characterized by symmetrical outlets and improved pressure relief capacity was developed. The novel structure and function of the new valve was first introduced, and comprehensive analysis regarding dynamic performances, strength and fluid development during the relief process were conducted. Finally, a prototype was manufactured and tested on a specific arcing test system. The developed valve can well release the overpressure generated by a 6 MJ equivalent arcing fault without any flame during the entire relief process. Furthermore, the valve structure can withstand the pressure load, and valve plate can precisely reseal the oil tank due to optimized fluid pressure distribution. This research provides an optimized pressure relief valve and a design guide for improved pressure relief valve.

Numerical study on strut insertion based thrust vectoring control system

PurposeThis study aims to numerically study the three-dimensional (3D) flow field characteristics in a conical convergent divergent (CD) nozzle with an internal strut system to describe the effect of struts on producing a side force for thrust vectoring applications.Design/methodology/approachStruts are solid bodies. When inserted into the supersonic region of the axisymmetric CD nozzle, it induces a shock wave that causes an asymmetric pressure distribution predominantly over the internal surface of the diverging wall of the C-D nozzle, creating a net side force similar to the secondary injection thrust vectoring control method. Numerical simulations were performed by solving Unsteady Reynolds Averaged Navier–Stokes equations with re-normalized group k–ϵ turbulence model. Cylindrical struts of various heights positioned at different locations in the divergent section of the nozzle were investigated at a nozzle pressure of 6.61.FindingsThrust vectoring angle of approximately 3.8 degrees was obtained using a single cylindrical strut with a dimensionless thrust (%) and total pressure loss of less than 2.36% and 2.67, respectively. It was shown that the thrust deflection direction could also be changed by changing the strut insertion location. A strut located at half of the diverging length produced a higher deflection per unit total pressure loss.Practical implicationsUsing a lightweight and high-temperature resistant material, such as a strut, strut insertion-based thrust vectoring control might provide an alternative thrust vectoring method in applications where a longer period of control is needed with a reduced overall system weight.Originality/valueThis study describes the 3D flow field characteristics which result in side force generation by a supersonic nozzle with an internal strut.

The mean pressure distribution on the free end of a square prism

In this experimental study, the mean pressure distribution was measured on the free end of a surface-mounted finite-height square prism for different aspect ratios, incidence angles, and boundary layer thicknesses. The Reynolds number based on the width of the prism was kept constant at Re = 6.5 × 104, the aspect ratio of the prism was changed from AR = 1 to 11, and the incidence angle was varied in small increments from α = 0° to 45°. The thickness of the boundary layer on the ground plane relative to the prism width was either δ/D = 0.8 or δ/D = 2.6, representing a thin or thick boundary layer. When the prism was oriented at α = 0°, distinct mean pressure distributions were observed for prisms nearly or completely immersed in the boundary layer, and also for the very slender high-aspect ratio prisms. The mean normal force coefficient steadily increased with the aspect ratio but its value decreased in the presence of the thicker boundary layer. When the prism was oriented at α = 45°, strong pressure gradients were encountered near the leading edges for prisms nearly or completely immersed in the boundary layer, and the conical vortex angles increased with aspect ratio. For intermediate aspect ratios, these pressure gradients weakened and the vortex angles became insensitive to AR. When the incidence angle was between 0° and 45°, the asymmetric mean pressure distribution meant that the conical vortices were located at different angles. The position of the conical vortex located more centrally above the free end was more sensitive to changes in aspect ratio. The influence of the boundary layer on the vortex angles was more pronounced for smaller aspect ratios. In addition, the behaviour of the normal force coefficient with incidence became more complex for higher aspect ratios.

On the dynamic behaviors of freely falling annular disks at different Reynolds numbers

Freely falling or rising objects in quiescent Newtonian fluid have been frequently encountered in nature or industry, such as the spreading of seeds from a tree or the movement of ores in deep sea mining. The dynamic behaviors of freely moving objects can provide a significant understanding of the evolution of the body wake and the resulting path instability. In this study, we present numerical simulations of freely falling annular disks released from quiescent water for relatively low Reynolds numbers from 10 to 500 while keeping the non-dimensional moment of inertia I* and inner to outer diameter ratio η constant. The falling stage experiences a variation from quasi-one-dimensional mode, steady oblique motion (SO motion), to the fully three-dimensional mode, helical motion. The stage diagram is plotted to show the variation tendency with the increment of Reynolds numbers. The detailed characteristics of the trajectories and orientation of the annular disks for different motions are analyzed. The corresponding vortical structures are presented, and an analog of the wingtip vortex is found at the outer rim of the disk for transitional and helical motion. A steady recirculation region of SO motion is observed, which is similar to that of a stationary disk but with complex multilayer structures formed by the combined effects of both the inner and outer rims. The limit streamline and pressure coefficient are investigated, demonstrating that the asymmetrical pressure distribution that exerts fluid forces and torques on the disk plays a crucial role in the dynamic response of the disk. Furthermore, combining the flow fields and fluid forces, the physical mechanism responsible for the diverse falling patterns is explored in detail.

Piezoresistive-Based Gait Monitoring Technique for the Recognition of Knee Osteoarthritis Patients

Knee osteoarthritis (Knee OA) is a degenerative disease that often perplexes the elderly and the whole society, and its timely recognition receives interest worldwide. However, traditional imaging examinations cannot reflect dynamic function nor implement long-term monitoring. To address this issue, this article suggests a piezoresistive-based gait monitoring method to recognize patients with Knee OA by assessing the plantar pressure signals during the subjects’ walking, which is mobile, wearable, low-cost, and convenient. Eighteen subjects diagnosed with Knee OA and twenty-two control subjects participated in the experiment. Considering the asymmetric pressure distribution in feet and the landing habits of Knee OA patients, the plantar surface was split into eight areas, calculating the contact time and maximum force of each area in a gait cycle. Using these characteristics to train, the support vector machine (SVM) reached an accuracy of 93.15%, a precision of 92.39%, and a recall of 92.79%. Furthermore, a prediction model was proposed for the application that aggregates all the results in one test and gives a more accurate result, and the classification accuracy for individuals in the ensemble model is 90.90%. Our technique fills the vacancy of the recognition of patients with Knee OA based on wearable instruments. It provides ideas for intelligent healthcare, which benefits potential Knee OA patients’ early diagnosis and treatment.

Three-Dimensional Finite Element Modeling of Blast Wave Transmission From the External Ear to a Spiral Cochlea.

Blast-induced injuries affect the health of veterans, in which the auditory system is often damaged, and blast-induced auditory damage to the cochlea is difficult to quantify. A recent study modeled blast overpressure (BOP) transmission throughout the ear utilizing a straight, two-chambered cochlea, but the spiral cochlea's response to blast exposure has yet to be investigated. In this study, we utilized a human ear finite element (FE) model with a spiraled, two-chambered cochlea to simulate the response of the anatomical structural cochlea to BOP exposure. The FE model included an ear canal, middle ear, and two and half turns of two-chambered cochlea and simulated a BOP from the ear canal entrance to the spiral cochlea in a transient analysis utilizing fluid-structure interfaces. The model's middle ear was validated with experimental pressure measurements from the outer and middle ear of human temporal bones. The results showed high stapes footplate (SFP) displacements up to 28.5 μm resulting in high intracochlear pressures and basilar membrane (BM) displacements up to 43.2 μm from a BOP input of 30.7 kPa. The cochlea's spiral shape caused asymmetric pressure distributions as high as 4 kPa across the cochlea's width and higher BM transverse motion than that observed in a similar straight cochlea model. The developed spiral cochlea model provides an advancement from the straight cochlea model to increase the understanding of cochlear mechanics during blast and progresses toward a model able to predict potential hearing loss after blast.

Theoretical analysis of a contactless transportation system for cylindrical objects based on ultrasonic levitation.

Contactless transportation systems based on near-field acoustic levitation have the benefit of compact design and easy control which are able to meet the cleanliness and precision demands required in precision manufacturing. However, the problems involved in contactless positioning and transporting cylindrical objects have not yet been addressed. This paper introduces a contactless transportation system for cylindrical objects based on grooved radiators. A groove on the concave surface of the radiator produces an asymmetrical pressure distribution which results in a thrusting force to drive the levitator horizontal movement. The pressure distribution between the levitator and the radiator is acquired by solving the Reynolds equation. The levitation and the thrusting forces are obtained by integrating the pressure and the pressure gradient over the concave surface, respectively. The predicted results of the levitation force agree well with experimental observations from the literature. Parameter studies show that the thrusting force increases and converges to a stable value as the groove depth increases. An optimal value for the groove arc length is found to maximize the thrusting force, and the thrusting force increases as the groove width, the radiator vibration amplitude, and the levitator weight increase.

Unsteady hot gas ingestion through the double rim-seals of an axial gas turbine

Rim-seals are exposed to one of the most complex flows in modern high-efficiency gas turbines. The flow physics in the vicinity of rim-seals should be understood before predicting the hot gas ingestion that may cause a rise in disc temperature and a catastrophic failure. To investigate the seal performance of rim-seals, experiments were performed using a high-speed rotating test-rig and followed up that the unsteady flow analysis approach was proposed. The rotating rig consisted of 1.5-stage axial turbines with a double rim-seal. Local pressures and CO2 concentrations were measured to evaluate flow characteristics and sealing performance. At a rotational Reynolds number of 1.0 × 106, the circumferential pressure distribution on the vane endwall platform and corresponding distribution of the circumferential sealing effectiveness of the rim-seal were measured. The results of the unsteady Reynolds-averaged Navier–Stokes (URANS) model were in a good agreement with the experimental results. Time-averaged, time-resolved flow observations under various conditions revealed unsteadiness of rim-seal flow; ingress and egress occurred repeatedly over time at all circumferential locations. The results validated unsteady ingestion from a reduction in sealing effectiveness of up to 30% at any instant compared to the time-averaged sealing effectiveness. As the rotational speed increased, the asymmetric pressure distribution of the main flow increased, and the average sealing effectiveness decreased up to 50%. The novelty of this study is that instantaneous hot gas-ingestions reached to a location significantly deeper into the disc cavity than that obtained from time-averaged predictions. It is concluded that understanding the nature of unsteady flow and its effects to hot gas-ingestion is vital to the reliable design of turbine rim-seals.

Wave overtopping flow striking a human body on the crest of an impermeable sloped seawall. Part II: Numerical modelling

The present paper is the second of two companion papers on the investigations of wave overtopping flow striking a cylinder, which is the schematisation of a human body, on the crest of an impermeable sloped seawall with a deep foreshore. This paper numerically examines the detailed characteristics of the overtopping flow and the force on the cylinder in-line with the flow direction by using a volume-of-fluid (VOF) based Reynolds-Averaged Navier-Stokes (RANS) model. The numerical model is successfully validated against the experimental data on the wave overtopping flow depth and the inline force on the cylinder. The characteristics of the overtopping flow velocity are analysed using the validated numerical model. It is observed that the maximum depth-averaged flow velocity usually occurs before the maximum flow depth during an overtopping event, and decay of the overtopping velocity is much slower than the flow depth along the seawall crest. For plunging-breaker cases, the overtopping force on the cylinder usually comprises a cycle of a first impact peak, a main peak and a secondary peak. However, for surging-breaker cases, it is largely dominated by the main peak. The first impact peak is due to the impact of the tip of the overtopping flow on the cylinder, which usually has a higher flow velocity than the main stream. The main peak is generated by the asymmetric pressure distribution around the cylinder, which co-occurs with the maximum local momentum flux of the overtopping flow. As the force decreases after the main peak, there sometimes exists a secondary peak, which is formed by the complex free surface motion locally behind the cylinder. Additional numerical experiments are presented to demonstrate the applicability of a simple maximum force predictor developed in Part I. A prototype-scale simulation of irregular waves overtopping a sloped seawall is conducted to obtain the maximum force. The predictor also gives the maximum force in a wave-by-wave manner using the incident wave condition. These two approaches produce very similar estimates, suggesting that the predictor can be used for engineering applications.

Study on the influence of linear and nonlinear distribution of crosswind on the motion of aircraft wake vortex

Environmental crosswind can greatly affect the development of aircraft wake vortex pair. Previous numerical simulations and experiments have shown that the nonlinear vertical shear of the crosswind velocity can affect the dissipation rate of the aircraft wake vortex, causing each vortex of the vortex pair descent with different velocity magnitude, which will lead to the asymmetrical settlement and tilt of the wake vortex pair. Through numerical simulations, this article finds that uniform crosswind convection and linear vertical shear crosswind convection can also have an effect on the strength of the vortex. This effect is inversely proportional to the cube of the vortex spacing, so it is more intense on small separation vortex pair. In addition, the superposition of crosswind and vortex-induced velocities will lead to the asymmetrical pressure distribution around the vortex pair, which will also cause the tilt of the vortex pair. Furthermore, a new analysis method for wake vortex is proposed, which can be used to predict the vortex trajectory.

Numerical Study of Surface Pressure Fluctuation on Rigid Disk-Gap-Band-Type Supersonic Parachutes

In the aerodynamic characteristics of supersonic parachutes, it is important to understand surface pressure distribution because it is strongly related to the fluctuation of drag and problematic unstable deformation of a parachute. However, there is a paucity of studies that focuses on the detailed surface pressure distribution. Therefore, we investigated the interior and exterior of a rigid disk-gap-band-type parachute as the first step, under the assumption that the forebody or suspension lines are absent, and thus the pressure and drag fluctuations are small. Two configurations are considered: one with a continuous gap and a vent orifice, representing a conventional Disk-Gap-Band parachute, and one with a discontinuous gap made up of 8 separate orifices and a vent orifice. By making the gap discontinuous, the interior and exterior pressure fluctuations are reduced. Furthermore, as indicated by the flowfield analysis, the discrete gap reduces the asymmetric pressure distribution interior the parachute, and the interior pressure fluctuation far from the center is suppressed. The result is considered useful for the suppression of unstable deformation such as area oscillation. This is currently a problem in supersonic parachute operation. In addition, we have identified locations on the model surface where the pressure fluctuations contribute to the drag fluctuations of the model.

Inline force on human body due to non-impulsive wave overtopping at a vertical seawall

Wave overtopping endangers pedestrians on a seawall’s crest area, but quantitative assessment of the risk is still a challenge. In this study, a circular cylinder is taken as a schematisation of human body. Physical model tests and numerical simulations were conducted to investigate the inline force on the cylinder due to overtopping flow at a vertical seawall. It is found that the overtopping flow is well reproduced by the numerical model. When the overtopping flow encounters the cylinder, a high pressure zone is developed on the front surface of the cylinder due to the local flow stagnation, while a shallow wake flow occurs behind the cylinder due to the blockage effect. The asymmetric pressure distribution produces the inline force on the cylinder. When the cylinder is further moved inland, the depth of the local overtopping flow it faces is smaller. However, the inline force does not decay accordingly, which is due to the variation of the flow velocity along the seawall’s crest. Finally, a predictor is developed for desktop computation of the maximum inline force. A prototype-scale numerical case study is carried out to demonstrate the capability of this predictor.

Electromagnetic separation of impurities in a conductive medium

A numerical study of the flow of an electrically conductive fluid is carried out in a cell under the action of a constant magnetic field. Distribution of electromotive force is investigated as well as the topology of electric current in the cell. The evolutions of velocity field are studied for different parameters. Two large scale unstable eddies are generated in the cell. The characteristic of the flow oscillations are determined using the wavelet analysis. It was found that an increase of current does not lead to the appearance of additional oscillation modes. Asymmetric pressure distribution may appear in the cell. Particle movement are possible due to the asymmetric pressure field.