Journal of Computational Physics

In this paper, we present a novel numerical scheme for simulating deformable and extensible capsules suspended in a Stokesian fluid. The main feature of our scheme is a partition-of-unity (POU) based representation of the surface that enables ...

• Develops a scheme for deformable capsules in Stokesian fluid.
• Employs integral equations with regularized Stokes kernels.
• Utilizes atlas-based finite differences for shape derivatives.
• Achieves O ( N ) complexity, surpassing O (...

To investigate the Brownian motion of individual particles suspended in viscoelastic fluids, the stochastic smoothed profile method (SPm) for direct numerical simulation is developed by extending deterministic SPm for suspensions in viscoelastic ...

• A direct simulation for particle dynamics in thermally driven viscoelastic flow is developed.
• Fluctuating viscoelasticity is combined with Smoothed profile method.
• Simulated thermally driven viscoelasitc flow and Brownian motion ...

We develop the stochastic Maxwell's equations with Drude model under both additive and multiplicative noises. The additive noises characterize the random fluctuations in the electric current and magnetic current densities in Maxwell's equations, ...

• The stochastic Maxwell's equations with Drude dispersion are developed under additive and multiplicative noises.
• The averaged global energy law is derived for the stochastic Maxwell's equations with Drude model under both types of ...

This fundamental study presents Navier-Stokes characteristic boundary conditions (NSCBCs) for high-enthalpy hypersonic flows in thermochemical non-equilibrium. In particular, the relevant locally one-dimensional inviscid (LODI) relations are ...

• Presents Navier-Stokes characteristic boundary conditions (NSCBCs) for hypersonic flows in thermochemical non-equilibrium.
• NSCBCs yield domain-insensitive solutions for canonical test cases subject to both chemical and vibrational ...

We present a component-based model order reduction procedure to efficiently and accurately solve parameterized incompressible flows governed by the Navier-Stokes equations. Our approach leverages a non-overlapping optimization-based domain ...

• Component-based model reduction to incompressible flows in repetitive geometries.
• Application of optimization-based formulation to non-overlapping domain decomposition.
• Static condensation of local degrees of freedom improves ...

In this work, we first develop a general mesoscopic multiple-relaxation-time lattice Boltzmann (MRT-LB) model for the two-dimensional diffusion equation with the constant diffusion coefficient and source term, where the D2Q5 (five discrete ...

• A general fourth-order MRT-LB model is developed for the two-dimensional diffusion equations.
• The macroscopic finite-difference scheme of the MRT-LB model is obtained theoretically.
• The accuracy and stability of the MRT-LB model ...

We present a partial-differential-equation-based optimal path-planning framework for curvature constrained motion, with application to vehicles in 2- and 3-spatial-dimensions. This formulation relies on optimal control theory, dynamic programming,...

We study the stability and sensitivity of an absorbing layer for the Boltzmann equation by examining the Bhatnagar–Gross–Krook (BGK) approximation and using the perfectly matched layer (PML) technique. To ensure stability, we discard some ...

• Some parameters need to be set to zero in order to ensure the stability of the BGK model with the PML.
• The most crucial parameters are the PML exponent and the PML thickness.
• The values of the total sensitivity indices do not ...

This paper presents a boundary element method (BEM) for computing the energy transmittance of a singly-periodic grating in 2D for a wide frequency band, which is of engineering interest in various fields with possible applications to acoustic ...

• A novel boundary element method for sweeping the acoustic transmittance of a singly-periodic slab is developed.
• The proposed method is based on the FMM and the hierarchical methods to compute the frequency derivatives of sound ...

This paper presents a model order reduction method to accelerate broadband topology optimization of structural-acoustic interaction systems by coupling Finite Element Methods and Boundary Element Methods. The finite element method is used for ...

• Broadband topology optimization of 3D structural-acoustic interaction with reduced order isogeometric FEM/BEM.
• Model order reduction is conducted for topology optimization of structural-acoustic interaction by coupling FEM/BEM.
• The ...

Constraints can be used to eliminate quickly fluctuating degrees of freedom in dynamical systems enabling solutions that resolve the behavior of the system with fewer time steps over long time scales. In Brownian dynamics models, these ...

In this article, an iterative method for nonlinear transmission lines (TLs) based on the Lax-Wendroff method has been established to describe a bidirectional coupling model of nonlinear lumped-element models, nonlinear transmission line models, ...

• This work presents a non-linear bidirectional coupling model merging transmission line, lumped element, and PIC models.
• The method uses generalized circuit equations for IMN solving, and charge and Poisson equations for the NTLM ...

This paper introduces a new immersed boundary (IB) method for viscous incompressible flow, based on a Fourier spectral method for the fluid solver and on the nonuniform fast Fourier transform (NUFFT) algorithm for coupling the fluid with the ...

• The FSIB method is gridless and has exact translation invariance.
• A divergence-free interpolated velocity field that conserves volume.
• Equivalent to the use of a new ‘sinc’ kernel in the framework of IB method.
• Improved ...

Statistical descriptions of particulate phases and granular media based on the notion of a property distribution are particularly advantageous for dense, many-particle dispersions since they support the direct evaluation of Eulerian property ...

• We present a Eulerian Monte Carlo (EMC) method for solving multivariate population balances.
• The particle property distribution is represented in terms of the total number density and an ensemble of property samples.
• In a spatial ...

Dynamical low-rank (DLR) approximation has gained interest in recent years as a viable solution to the curse of dimensionality in the numerical solution of kinetic equations including the Boltzmann and Vlasov equations. These methods include the ...

Deterministic transport codes play a fundamental role in the modeling and simulation of neutron transport. One of the most common deterministic methods is the method of discrete ordinates, also known as the S_n method. While offering significant ...

• Sn methods suffer from numerical artifacts known as ray effects.
• First collision source treatment methods help mitigate ray effects.
• The surface method is inherently conservative and has high potential for optimization.

The semiclassical (or Hagedorn) wavepackets depending on a fixed set of parameters are an orthonormal L 2-basis of generalized coherent states. They have been used to solve numerically the time-dependent Schrödinger equation in its semiclassical ...

• A family of semiclassical wavepackets is a localized orthonormal basis, i.e. inefficient in case of non-localized phenomena.
• A new algorithm to expand a given wavefunction in terms of multiple families of wavepackets is presented.
• ...

In this paper we propose an improved three-dimensional immersed boundary method coupled with a finite-difference code to simulate self-propelled phoretic particles in viscous incompressible flows. We focus on the phenomenon of diffusiophoresis ...

• We correct immersed boundary terms through the addition of forces from previous time steps.
• The approach departs from traditional methods that rely solely on instantaneous forces, enhancing simulation accuracy.
• The study presents a ...

A data-driven projection-based reduced-order model (ROM) for nonlinear thermal radiative transfer (TRT) problems is presented. The TRT ROM is formulated by (i) a hierarchy of low-order quasidiffusion (aka variable Eddington factor) equations for ...

• A structure and asymptotic preserving reduced-order model is derived for solving non-linear radiation wave problems.
• A POD-Petrov-Galerkin projection of the normalized Boltzmann transport equation scaled with material opacities is ...

In this paper, we propose a unified framework for studying the Cahn–Hilliard equation with two distinct types of dynamic boundary conditions, namely, the Allen–Cahn and Cahn–Hilliard types. Using this unified framework, we develop a linear, ...

In this communication, the propagation of poroacoustic acceleration waves in a class of inhomogeneous gases whose ambient mass density varies exponentially is considered. Employing the tools of singular surface theory, we first determine the ...

• Krylov subspace spectral (KSS) methods can effectively model acoustic singular surfaces with large CFL numbers.
• Unlike other spectral methods, their component-wise approach enables accurate solution even without smoothing.
• KSS ...

This article presents a general reduced order model (ROM) framework for addressing fluid dynamics problems involving time-dependent geometric parametrisations. The framework integrates Proper Orthogonal Decomposition (POD) and Empirical Cubature ...

• General reduced order model (ROM) framework for time-dependent geometric parametrisations.
• Study of the hysteresis of the Coanda Effect for a contraction-expansion channel in a ROM context.
• Presentation of the empirical cubature ...

Field inversion is often encountered in data-driven computational modeling to infer latent spatial–varying parameters from available observations. The ensemble Kalman method is emerging as a useful tool for solving field inversion problems due to ...

• The analysis scheme of the ensemble Kalman method is parallelized based on non-overlapping domain decomposition.
• The total variation regularization is utilized to alleviate the discontinuity near subdomain interfaces.
• The method ...

In this work, a bound- and positivity-preserving quasi-conservative discontinuous Galerkin (DG) method is proposed for the γ-based model of compressible two-medium flows. The contribution of this paper mainly includes three parts. On one hand, ...