scholarly journals A meshfree finite volume method with optimal numerical integration and direct imposition of essential boundary conditions

2020 ◽  
Vol 153 ◽  
pp. 98-113
Author(s):  
Hengguang Li ◽  
Qinghui Zhang
Keyword(s):  
Boundary Conditions ◽  
Finite Volume Method ◽  
Numerical Integration ◽  
Finite Volume ◽  
Volume Method

Modelling Transsonic Flows Through Ring-Shape Thruster Geometries With DSMC

2012 ◽  
Author(s):  
Rodion Groll ◽  
Fabian Fastabend ◽  
Hans J. Rath
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Mirror Reflection ◽  
Nozzle Throat ◽  
Space Applications ◽  
Lower Velocity ◽  
Ring Shape ◽  
Volume Method

When modeling rarefied gas flows, continuous approximation is limited by the Knudsen regime. The presented cold gas thruster for space applications is investigated for pressure values lying between 10−2 and 103 Pa. It is comprised of a subsonic funnel region, a transsonic region consisting of a ring-shaped nozzle throat and a supersonic diffuser region. Diffusive and specular / mirror reflection is used to describe the behavior of particle/wall collision in the discrete model. Simulation results are compared both with experimental data and with numerical results computed using a finite-volume method. The transsonic flow through the nozzle throat shows very good agreement with experimental data. Simulation and experimental results emphasize the influence of various geometric factors like size and shape of the nozzle throat. Furthermore, differences in the acceleration behavior of Argon and Xenon are examined. Results of simulations utilizing the DSMC method [Bird, 1994, Stefanov et al., 2011] with diffusively reflecting boundary conditions present the best agreement with experimental data. Any deviation seen using the finite-volume method with no-slip boundary conditions can be explained by the equilibrium gas-state near the walls [Brenner, 2005, Greenshields et al., 2007]. The non-equilibrium approach produces lower velocity gradients near the wall, especially in wall regions with high levels of surface curvature.

scholarly journals The high hall ventilation with the simplified simulation of the fan

2018 ◽  
Vol 180 ◽  
pp. 02051
Author(s):  
Martin Kyncl ◽  
Jaroslav Pelant
Keyword(s):  
Numerical Simulation ◽  
Gravitational Field ◽  
Boundary Conditions ◽  
Finite Volume Method ◽  
Riemann Problem ◽  
Finite Volume ◽  
Unstructured Meshes ◽  
System Of Equations ◽  
Computational Results ◽  
Volume Method

Here we work with the system of equations describing the non-stationary compressible turbulent multi-component flow in the gravitational field. We focus on the numerical simulation of the fan situated inside the high hall. The RANS equations are discretized with the use of the finite volume method. The original modification of the Riemann problem and its solution is used at the boundaries. The combination of specific boundary conditions is used for the simulation of the fan. The presented computational results are computed with own-developed code (C, FORTRAN, multiprocessor, unstructured meshes in general).

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