scholarly journals Investigation of the Contamination Control in a Cleaning Room with a Moving AGV by 3D Large-Scale Simulation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Qing-He Yao ◽  
Qing-Yong Zhu
Keyword(s):  
Domain Decomposition ◽  
Large Scale ◽  
High Efficiency ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Past Research ◽  
Navier Stokes ◽  
Preconditioned Conjugate Gradient ◽  
Contamination Control ◽  
Large Scale Simulation

The motions of the airflow induced by the movement of an automatic guided vehicle (AGV) in a cleanroom are numerically studied by large-scale simulation. For this purpose, numerical experiments scheme based on domain decomposition method is designed. Compared with the related past research, the high Reynolds number is treated by large-scale computation in this work. A domain decomposition Lagrange-Galerkin method is employed to approximate the Navier-Stokes equations and the convection diffusion equation; the stiffness matrix is symmetric and an incomplete balancing preconditioned conjugate gradient (PCG) method is employed to solve the linear algebra system iteratively. The end wall effects are readily viewed, and the necessity of the extension to 3 dimensions is confirmed. The effect of the high efficiency particular air (HEPA) filter on contamination control is studied and the proper setting of the speed of the clean air flow is also investigated. More details of the recirculation zones are revealed by the 3D large-scale simulation.

scholarly journals Study of Indoor Ventilation Based on Large-Scale [DNS by a Domain Decomposition Method

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1416
Author(s):  
Jiang ◽  
Jiang ◽  
Kwan ◽  
Liu ◽  
Yao
Keyword(s):  
Domain Decomposition ◽  
Decomposition Method ◽  
Large Scale ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Numerical Data ◽  
Transient Behavior ◽  
Preconditioned Conjugate Gradient ◽  
Interface Problem ◽  
Indoor Airflow

This paper presents a large-scale Domain Decomposition Method (DDM) based Direct Numerical Simulation (DNS) for predicting the behavior of indoor airflow, where the aim is to design a comfortable and efficient indoor air environment of modern buildings. An analogy of the single-phase convection problems is applied, and the pressure stabilized domain decomposition method is used to symmetrize the linear systems of Navier-Stokes equations and the convection-diffusion equation. Furthermore, a balancing preconditioned conjugate gradient method is utilized to deal with the interface problem caused by domain decomposition. The entire simulation model is validated by comparing the numerical results with that of recognized experimental and numerical data from previous literature. The transient behavior of indoor airflow and its complexity in the ventilated room are discussed; the velocity and vortex distribution of airflow are investigated, and its possible influence on particle accumulation is classified.

ANALYSIS OF A HETEROGENEOUS DOMAIN DECOMPOSITION FOR COMPRESSIBLE VISCOUS FLOW

2001 ◽  
Vol 11 (04) ◽  
pp. 565-599 ◽  
Author(s):  
CRISTIAN A. COCLICI ◽  
WOLFGANG L. WENDLAND
Keyword(s):  
Domain Decomposition ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Near Field ◽  
Outer Region ◽  
Navier Stokes ◽  
Far Field ◽  
Computational Domain ◽  
Linearized Euler Equations ◽  
Naca0012 Airfoil

We analyze a nonoverlapping domain decomposition method for the treatment of two-dimensional compressible viscous flows around airfoils. Since at some distance to the given profile the inertial forces are strongly dominant, there the viscosity effects are neglected and the flow is assumed to be inviscid. Accordingly, we consider a decomposition of the original flow field into a bounded computational domain (near field) and a complementary outer region (far field). The compressible Navier–Stokes equations are used close to the profile and are coupled with the linearized Euler equations in the far field by appropriate transmission conditions, according to the physical properties and the mathematical type of the corresponding partial differential equations. We present some results of flow around the NACA0012 airfoil and develop an a posteriori analysis of the approximate solution, showing that conservation of mass, momentum and energy are asymptotically attained with the linear model in the far field.

scholarly journals Large Scale Simulation of Hydrogen Dispersion by a Stabilized Balancing Domain Decomposition Method

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Qing-He Yao ◽  
Xin Pan
Keyword(s):  
Domain Decomposition ◽  
Decomposition Method ◽  
Large Scale ◽  
Open Space ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Concentration Field ◽  
Numerical Results ◽  
Interface Problem ◽  
Balancing Domain Decomposition

The dispersion behaviour of leaking hydrogen in a partially open space is simulated by a balancing domain decomposition method in this work. An analogy of the Boussinesq approximation is employed to describe the connection between the flow field and the concentration field. The linear systems of Navier-Stokes equations and the convection diffusion equation are symmetrized by a pressure stabilized Lagrange-Galerkin method, and thus a balancing domain decomposition method is enabled to solve the interface problem of the domain decomposition system. Numerical results are validated by comparing with the experimental data and available numerical results. The dilution effect of ventilation is investigated, especially at the doors, where flow pattern is complicated and oscillations appear in the past research reported by other researchers. The transient behaviour of hydrogen and the process of accumulation in the partially open space are discussed, and more details are revealed by large scale computation.

Parallelized Domain Decomposition Techniques for Multiphase Flow

Volume 3 ◽  
2004 ◽  
Author(s):  
Eray Uzgoren ◽  
Wei Shyy ◽  
Marc Garbey
Keyword(s):  
Domain Decomposition ◽  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Computational Cost ◽  
Navier Stokes ◽  
Immersed Boundary ◽  
Pressure Poisson Equation ◽  
Boundary Method ◽  
Additive Schwarz Method

Direct simulation of multiphase flows is a challenging task due to the moving interface and property variations between phases. In this study, a parallel domain decomposition method is implemented for such flows to lower the computing cost. Specifically, the approach consists of the additive Schwarz method for domain decomposition, the projection method for the Navier-Stokes equations, the immersed boundary method for treating the interfacial dynamics, and the multigrid method to expedite the solution of the pressure Poisson equation. The issues related to load balancing, communication and computation, scalability in regard to grid size and the number of processors, and interface shape deformation, are studied using both SGI Altix and Linux-based Beowulf systems. As the number of processors increases, as expected, the domain decomposition technique results in modest decrease in convergence rate, while the multigrid technique is effective in reducing the computational cost. The additional computational cost incurred by the immersed boundary method for tracking the interface is not significant.

scholarly journals A domain decomposition method for the Navier–Stokes equations with stochastic input

2021 ◽  
Vol 40 (5) ◽  
Author(s):  
Junxiang Lu ◽  
Jin Su
Keyword(s):  
Constrained Optimization ◽  
Domain Decomposition ◽  
Gradient Method ◽  
Decomposition Method ◽  
Stokes Equations ◽  
Optimization Problems ◽  
Domain Decomposition Method ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Stochastic Input

AbstractThe paper is committed to studying the domain decomposition method for the incompressible Navier–Stokes equations(NSEs) with stochastic input. The stochastic input is represented spectrally by employing orthogonal polynomial functionals from the Askey scheme as trial basis to represent the random space, and the stochastic NSEs system are transformed into deterministic ones via the polynomial chaos expansion. The corresponding deterministic equations are transformed into the constrained optimization problem by minimizing the cost function on the common interface after the whole domain decomposed into two sub-domains. The constrained optimization problems are transformed into unconstrained problems by the Lagrange multiplier rule. A gradient method-based approach to the solutions of domain decomposition problem is proposed to solve the unconstrained optimality system. Finally, one numerical simulation experiment for square cavity flow problem with the stochastic boundary conditions are performed to demonstrate the feasibility and applicability of the gradient method.

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