A robust overset assembly method allowing for multiple overlapping bodies is presented. This method extends the overset assembly method to deal with the interference between objects and prevents the failure of the search for donor cells due to the complex shape of the models. The donor cells are searched before identifying the boundary of the chimera interpolation. By selecting interpolation cells

This article presents an algorithm for constraining shape deformations in adjointbased aerodynamic shape optimization. The algorithm considers known bounding surfaces and constrains the shape undergoing optimization not to intersect with them. For each and every node on the shape, its signed distance to the bounding surfaces is computed. The signed distance function returns a positive value, in case

In this paper, we discuss the numerical approximation to solve regular tempered fractional Sturm‐Liouville problem (TFSLP) using finite difference method. The tempered fractional differential operators considered here are of Caputo type. The numerically obtained eigenvalues are real, and the corresponding eigenfunctions are orthogonal. The obtained eigenfunctions work as basis functions of weighted

Numerical models based on the two‐dimensional shallow water equations (2D‐SWE) are routinely used in flood risk management and inundation studies. However, most of these models do not adequately account for vertically confined flow conditions that can appear during inundations, due to the presence of hydraulic structures such as bridges, culverts or underground river reaches. In this paper we propose

A novel approach for selecting appropriate reconstructions is implemented to the hyperbolic conservation laws in the high‐order local polynomial‐based framework, e.g., the discontinuous Galerkin (DG) and flux reconstruction (FR) schemes. The high‐order polynomial approximation generally fails to correctly capture a strong discontinuity inside a cell due to the Gibbs phenomenon, which is replaced by

In this paper, the Random Phase Shift Method (RPSM) dealiasing scheme has been developed with the classical fourth order explicit Runge Kutta (RK4) method. This scheme is implemented in different benchmark problems to verify its numerical accuracy and computational efficiency where strong gradients are present in the solution. The propagation of aliasing errors through the sub‐steps of RK4 is derived

This paper introduces an e_cient numerical scheme for the solution of the Benjamin‐Bona‐Mahony equation. The scheme is fully implicit, and combines high‐order time stepping and a hybridizable discontinuous Galerkin method in space. Implicit time stepping allows for larger time steps, while remaining robust for long‐time simulations. It is shown that the scheme is energy stable, and conserves mass.

A new approach for the coupled simulation of moored floating structures in a numerical wave tank using CFD is subject of this paper. A quasi‐static mooring model is derived by dividing the cable into finite elements and solve force equilibria in each time step. A successive approximation is applied to solve the problem most efficiently. Here, the unknown internal and external forces are separated,

The cavitation bubbles that collapse in the hydraulic machinery can cause damage to the structure and the internal wall. In order to find feasible preventive measures, the mechanism of cavitation bubble collapse needs to be thoroughly studied. However, the influence of the initial radius or the interaction between multi‐bubbles has not been studied in depth. In this paper, the collapse process of single

In this paper, we consider a non‐local (in time) two‐phase flow model. The nonlocality is introduced through the wettability alteration induced dynamic capillary pressure function. We present a monotone fixed‐point iterative linearization scheme for the resulting non‐standard model. The scheme treats the dynamic capillary pressure functions semi‐implicitly and introduces an L ‐scheme type1,2 stabilization

Reduced‐order models are more and more considered for use in aerodynamic applications. Benefits of these methods can be expected for optimization problems or predicting aerodynamic loads for the entire flight envelope. For these applications it is often possible to perform computations for various parameter combinations before any ROM evaluations are needed. The order reduction of the CFD solutions

Computational fluid dynamics (CFD) has emerged as a successful tool for industry applications and basic science during the last decades. However, accurate solutions involving vortex propagation, and separated and turbulent flows, are still associated with high computing costs. In particular, large eddy simulations (LES) of complex geometries, such as a complete automobile, require several days on thousands

In this paper, we describe a parallel adaptive mesh refinement strategy for two‐phase flows using tetrahedral meshes. The proposed methodology consists of combining a conservative level‐set method with tetrahedral adaptive meshes within a finite volume framework. Our adaptive algorithm applies a cell‐based refinement technique and adapts the mesh according to physics‐based refinement criteria defined

In the present paper, an improved multiphase weakly compressible smoothed particle hydrodynamics model for balancing the accuracy and stability of the long‐term simulations is proposed to model the forced liquid sloshing in a tank. The governing equations of the multiphase flow are discretized by considering the density discontinuity over the interface. To suppress the pressure oscillation, a previous

No abstract is available for this article.

In this work, we present the results obtained from integrating several machine learning models with projection‐based reduced order model for modeling the canonical case of flow past a stationary cylinder. We demonstrate how machine learning models can be used to model the time‐varying characteristics of the POD coefficients, and that the locally‐interpolating models such as regression trees and k‐nearest

In this work, we consider a hyperbolic one‐dimensional (1D) model for blood flow through compliant axi‐symmetric tilted vessels. The pressure is a function of the cross‐sectional area and other model parameters. Important features of the model are inherited at the discrete level by the numerical scheme. For instance, the existence of steady states may provide important information about the flow properties

The paper presents the results of numerical analysis of acoustic impact generated by small finite source on heat and mass transfer of fluid‐saturated granular medium in a cavity heated from below. Thermodynamically consistent model of two‐phase medium is obtained by the method of conservation laws suggesting no equilibrium in pressure between the phases. The transition from diffusive to convective

Based on phase‐field theory, we develop a simple and robust single relaxation time (SRT) lattice Boltzmann (LB) model for simulating complex multiphase flows with large density ratios (up to 2000). The approach utilizes two lattice Boltzmann equations (LBE), one is used to describe the interface behavior and the other is used to calculate the hydrodynamic properties. To improve the accuracy and stability

Nowadays, aerodynamic computational modelling is carried out on a daily basis in an industrial setting. This is done with the aim of predicting the performance and flow characteristics of new components. However, limited resources in terms of time and hardware force the engineer to employ relatively coarse computational grids, thus achieving results with variable degree of inaccuracy.

This paper presents a new spectral model for solving the fully nonlinear potential flow problem for water waves in a single horizontal dimension. At the heart of the numerical method is the solution to the Laplace equation which is solved using a variant of the σ‐transform. The method discretizes the spatial part of the governing equations using the Galerkin method and the temporal part using the classical

High‐speed compressible turbulent flows typically contain discontinuities and have been widely modelled using Weighted Essentially Non‐Oscillatory (WENO) schemes due to their high‐order accuracy and sharp shock capturing capability. However, such schemes may damp the small scales of turbulence, and result in inaccurate solutions in the context of turbulence‐resolving simulations. In this connection

A novel Piecewise Circular Interface Construction (PCIC) method for accurate reconstruction of interface in a two phase flow problem is proposed. This is under the framework of a fixed grid, Volume of Fluid (VOF) approach applied on a two dimensional semi‐ staggered structured grid. Fluid interface in each mixed cell is represented using a geometric template of piecewise circular arc. Data corresponding

Corrective matrix that is derived to restore consistency of discretization schemes can significantly enhance accuracy for the inside particles in the Moving Particle Semi‐implicit (MPS) method. In this situation, the error due to free surface and wall boundaries becomes dominant. Based on the recent study on Neumann boundary condition (Matsunaga et al. CMAME, 2020), the corrective matrix schemes in

Combiningthe Navier‐Stokes systems with Neumann (or natural) boundary condition to characterize a fluid flow is frequent. The popular projection (or pressure correction) methods inspired by Chorin and Temam are not well adapted to such boundary condition, which translate in loss of accuracy. If some alternative projection methods have been proposed to reduce the accuracy loss due to the Neumann condition

No abstract is available for this article.

The dynamics of membranes, shells, and capsules in fluid flow has become an active research area in computational physics and computational biology. The small thickness of these elastic materials enables their efficient approximation as a hypersurface, which exhibits an elastic response to in‐plane stretching and out‐of‐plane bending, possibly accompanied by a surface tension force. In this work, we