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Flash flooding has become more prominent under climate change, threatening people's life and property. Post‐event investigations of recent events emphasize the role of floating debris, such as vehicles, in exacerbating damage. Few modeling methods and tools have been developed to simulate the full‐process dynamics of floating debris driven by large‐scale flood waves in real world. In this work, a fully coupled model is developed for simulating the full‐process interactive movements of vehicles driven by flash flood hydrodynamics, from entrainment, transport to deposition. The proposed coupled modeling system consists of a finite volume shock‐capturing hydrodynamic model solving the 2D shallow water equations and a 3D discrete element method (DEM) model. The proposed two‐way coupling approach estimates the hydrostatic and hydrodynamic forces acting on solid objects using the water depth and velocity predicted by the hydrodynamic model; the resulting counter forces on the fluid flow are then considered by adding extra source terms in the hydrodynamic model. A multi‐sphere method is further embedded in the DEM model to better represent vehicle shapes. New calculation modules are further implemented to represent the vehicle entrainment, contact and stopping motions. The coupled model is applied to reproduce a flash flood event hit Boscastle in the UK in 2004. Over 100 vehicles were moved and carried downstream by the highly transient flood flow. The model well predicts the hydrodynamics, interactive transport process and the final locations of vehicles. The proposed coupled model provides a new tool for simulating large‐scale flash flooding processes, including debris dynamics. Key Points A new coupled model for simulation of entrainment, transport and deposition of vehicles driven by and interacting with flood hydrodynamics The model is used to reproduce a flash flood event that moved over 100 vehicles, with results consistent with post‐event report and survey Increasing number of floating vehicles alters flood hydrodynamics and intensifies debris‐debris and debris‐fluid interactions

Mouse models provide unique opportunities to study vascular disease, but they demand increased experimental and computational resolution. We describe a workflow for combining in vivo and in vitro biomechanical data to build mouse-specific computational models of the central vasculature including regional variations in biaxial wall stiffness, thickness and perivascular support. These fluid–solid interaction models are informed by micro-computed tomography imaging and in vivo ultrasound and pressure measurements, and include mouse-specific inflow and outflow boundary conditions. Hence, the model can capture three-dimensional unsteady flows and pulse wave characteristics. The utility of this experimental–computational approach is illustrated by comparing central artery biomechanics in adult wild-type and fibulin-5 deficient mice, a model of early vascular ageing. Findings are also examined as a function of sex. Computational results compare well with measurements and data available in the literature and suggest that pulse wave velocity, a spatially integrated measure of arterial stiffness, does not reflect well the presence of regional differences in stiffening, particularly those manifested in male versus female mice. Modelling results are also useful for comparing quantities that are difficult to measure or infer experimentally, including local pulse pressures at the renal arteries and characteristics of the peripheral vascular bed that may differ with disease.

Bicuspid aortic valve (BAV) anatomy has routinely been considered an exclusion in the setting of transcatheter aortic valve implantation (TAVI) because of the large dimension of the aortic annulus having a more calcified, bulky, and irregular shape. The study aims to develop a patient-specific computational framework to virtually simulate TAVI in stenotic BAV patients using the Edwards SAPIEN 3 valve (S3) and its improved version SAPIEN 3 Ultra and quantify stent frame deformity as well as the severity of paravalvular leakage (PVL). Specifically, the aortic root anatomy of n.9 BAV patients who underwent TAVI was reconstructed from pre-operative CT imaging. Crimping and deployment of S3 frame were performed and then followed by fluid-solid interaction analysis to simulate valve leaflet dynamics throughout the entire cardiac cycle. Modeling revealed that the S3 stent frame expanded well on BAV anatomy with an elliptical shape at the aortic annulus. Comparison of predicted S3 deformity as assessed by eccentricity and expansion indices demonstrated a good agreement with the measurement obtained from CT imaging. Blood particle flow analysis demonstrated a backward blood jet during diastole, whereas the predicted PVL flows corresponded well with those determined by transesophageal echocardiography. This study represents a further step towards the use of personalized simulations to virtually plan TAVI, aiming at improving not only the efficacy of the implantation but also the exploration of “off-label” applications as the TAVI in the setting of BAV patients.

The efficient dynamic modeling and vibration transfer analysis of a fluid-delivering branch pipeline (FDBP) are essential for analyzing vibration coupling effects and implementing vibration reduction optimization. Therefore, this study proposes a reduced-order dynamic modeling method suitable for FDBPs and then analyzes the vibration transfer characteristics. For the modeling method, the finite element method and absorbing transfer matrix method (ATMM) are integrated, considering the fluid-structure coupling effect and fluid disturbances. The dual-domain dynamic substructure method is developed to perform the reduced-order modeling of FDBP, and ATMM is adopted to reduce the matrix order when solving fluid disturbances. Furthermore, the modeling method is validated by experiments on an H-shaped branch pipeline. Finally, transient and steady-state vibration transfer analyses of FDBP are performed, and the effects of branch locations on natural characteristics and vibration transfer behavior are analyzed. Results show that transient vibration transfer represents the transfer and conversion of the kinematic, strain, and damping energies, while steady-state vibration transfer characteristics are related to the vibration mode. In addition, multiple-order mode exchanges are triggered when branch locations vary in frequency-shift regions, and the mode-exchange regions are also the transformation ones for vibration transfer patterns.

Excess Flow Valves (EFV) for gas-stop systems is generally used in natural gas pipelines to prevent possible damages or destruction due to gas leakage. It can be used in a wide operating range of pressure, but the shut-off flow rate could be in various values at different pressures since natural gas can easily be compressed and can reach higher density. In this study, shut-off and nominal gas flow which effect on a spring force attached to an EFV system simulation by using Fluid Solid Interaction (FSI) strategy was studied. Furthermore, User Define Function (UDF) adapted to simulation to obtain the time-dependent deformation of the spring. The simulations were repeated at five different operating pressures (1-5 bar) with changing flow rates to show if EFV can shut-off the system or not. Results were validated against experimental data of the EFV to show the consistency of the FSI strategy. Moreover, detailed behaviour information of the EFV obtained by means.

Applying numerical simulation technology to investigate fluid-solid interaction involving complex curved boundaries is vital in aircraft design, ocean, and construction engineering. However, current methods such as Lattice Boltzmann (LBM) and the immersion boundary method based on solid ratio (IMB) have limitations in identifying custom curved boundaries. Meanwhile, IBM based on velocity correction (IBM-VC) suffers from inaccuracies and numerical instability. Therefore, this study introduces a high-accuracy curve boundary recognition method (IMB-CB), which identifies boundary nodes by moving the search box, and corrects the weighting function in LBM by calculating the solid ratio of the boundary nodes, achieving accurate recognition of custom curve boundaries. In addition, curve boundary image and dot methods are utilized to verify IMB-CB. The findings revealed that IMB-CB can accurately identify the boundary, showing an error of less than 1.8% with 500 lattices. Also, the flow in the custom curve boundary and aerodynamic characteristics of the NACA0012 airfoil are calculated and compared to IBM-VC. Results showed that IMB-CB yields lower lift and drag coefficient errors than IBM-VC, with a 1.45% drag coefficient error. In addition, the characteristic curve of IMB-CB is very stable, whereas that of IBM-VC is not. For the moving boundary problem, LBM-IMB-CB with discrete element method (DEM) is capable of accurately simulating the physical phenomena of multi-moving particle flow in complex curved pipelines. This research proposes a new curve boundary recognition method, which can significantly promote the stability and accuracy of fluid-solid interaction simulations and thus has huge applications in engineering.

The work concerns dynamic similarity criteria of various phenomena occurring in hydraulics and fluid dynamics originally derived from ratios of forces and forces moments affecting these phenomena. The base of dynamic similarity criteria formulations and considerations is A. Flaga’s method and procedure for determining dynamic similarity criteria in different issues of fluid–solid interactions i.e. at different fluid–solid relative motions. The paper concerns the determination and analysis of dynamic similarity criteria for various practical problems encountered mainly in hydraulics and fluid dynamics at steady, smooth fluid onflow in front of a solid. Moreover, the cases of mechanically induced vibrations of a body in a stationary fluid moving with constant velocity in front of the body have been presented. Assuming authorial method and procedure for determining dynamic similarity criteria, its have been presented and analysed in the paper both well known similarity numbers obtained in another way (e.g. from dimensional analysis or differential equations for particular problems – as Reynolds, Froude, Euler, Cauchy, Strouhal, Mach numbers) – as well as several new similarity numbers encountered in different fluid solid interaction problems (e.g. new forces and moments coefficients encountered in problems of vibrating solid bodies in fluids).

As the size and flexibility of wind turbine blades increase, the aeroelastic challenges faced by wind turbines become more pronounced. To prevent blade damage due to vibration and improve the aeroelastic stability of wind turbine blades, this paper proposes a bionic blade with a bionic web inspired by bamboo and honeycomb structures. The fluid-solid interaction analysis of the blades is conducted using computational fluid dynamics and the finite element method, based on the Shear Stress Transport (SST) k-w turbulence model. The displacements, stresses, strains, modal, and harmonic response analyses of both the original and bionic blades are evaluated underrated operating conditions. The results indicate that, compared to the original blade, the maximum displacement of the bionic blade is reduced by 10.1%, the maximum stress value on the blade surface is 2.1% lower, and the maximum strain value is 2.5% lower. The bamboo honeycomb web buffers wind loads in stages during the vibration and deformation of the bionic blade, leading to reduced vibration displacement and improved deformation resistance.

A two-phase flow model accelerated by graphical processing unit (GPU) is developed to solve fluid-solid interaction (FSI) using the sharp-interface immersed boundary method (IBM). This model solves the incompressible Navier-Stokes equations using the projection-based fractional step method in a fixed staggered Cartesian grid system. A volume of fluid (VOF) method with second-order accuracy is employed to trace the free surface. To represent the intricate surface geometry, the structure is discretized using the unstructured triangle mesh. Additionally, a ray tracing method is employed to classify fluid and solid points. A high-order stable scheme has been introduced to reconstruct the local velocity at interface points. Three FSI problems, including wave evolution around a breakwater, interaction between a periodic wave train and a moving float, and a 3-D moving object interacting with the free surface, were investigated to validate the accuracy and stability of the proposed model. The numerical results are in good agreement with the experimental data. Additionally, we evaluated the computational performance of the proposed GPU-based model. The GPU-based model achieved a 42.29 times speedup compared with the single-core CPU-based model in the three-dimension test. Additionally, the results regarding the time cost of each code section indicate that achieving more significant acceleration is associated with solving the turbulence, advection, and diffusion terms, while solving the pressure Poisson equation (PPE) saves the most time. Furthermore, the impact of grid number on computational efficiency indicates that as the number of grids increases, the GPU-based model outperforms the multi-core CPU-based model.

The article deals with a current state-of-art of fluid solid interaction (FSI) – the new branch of continuum physics. Fluid-solid interaction is a new quality of modeling physical processes of continuum mechanics, it can be described as the interaction of various (so far treated separately from the point of view of mathematical modeling) physical phenomena occurring in continuous media systems. The most correct is the simultaneous application of the laws of the given physical disciplines, which implies that fluid solid interaction is a subset of multi-physical applications where the interactions between these subsets are exchanged on the surface in interconnected systems. Our purpose is to extend the fluid solid interaction aplications into new phenomena what follow from the industrial needs and inovative thechnologies. Selecting the various approaches, we prefer the arbitraty lagrangean-eulerian description within the bulk of fluid/solid domain and a new sort of advanced boundary condition on a surface of common contact.