Effect of Using Near and Off-body Grids with Grid Adaption to Simulate Airplane Geometries

2011 ◽  
Author(s):  
Henry Lee ◽  
Thomas Pulliam
Keyword(s):  
Grid Adaption

Simulations of Unsteady Valve Systems

2005 ◽  
Author(s):  
V. Ahuja ◽  
A. Hosangadi ◽  
P. A. Cavallo ◽  
R. J. Ungewitter ◽  
J. D. Shipman
Keyword(s):  
Dynamic Instability ◽  
Fluid Dynamic ◽  
Control Valve ◽  
Industrial Facilities ◽  
Control Valves ◽  
Grid Adaption ◽  
Instability Modes ◽  
Multi Phase Flow ◽  
Valve Operation ◽  
Multi Phase

The safe and reliable operation of industrial facilities and high pressure test stands for engine and component testing is largely dependent on the smooth performance of control valves. However, such valves frequently experience pressure oscillations from hydrodynamic instabilities, cavitation and unsteady valve operation. In this paper, we present a series of high fidelity computational simulations of control valves primarily to understand the physics associated with the dominant instability modes. A generalized multi-element framework with sub-models for grid adaption, grid movement and multi-phase flow dynamics was used to carry out the simulations. We discuss the methodology in detail with the example of transient analyses of a gaseous hydrogen control valve and capture the fluid dynamic instability that results from valve operation. Additionally, we provide detailed analyses of a modal instability that is observed in the operation of a pressure regulator valve. In both cases, the instabilities are not localized and manifest themselves as a system wide phenomena leading to oscillations in mass flow and/or undesirable chatter.

Interactive numberical simulation and grid adaption for hypersonic flow

1992 ◽  
Vol 3 (1-4) ◽  
pp. 401-411
Author(s):  
E. Laurien ◽  
H. Holthoff ◽  
J. Wiesbaum
Keyword(s):  
Hypersonic Flow ◽  
Grid Adaption

scholarly journals Parallel Mesh Adaptive Techniques Illustrated with Complex Compressible Flow Simulations

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Pénélope Leyland ◽  
Angelo Casagrande ◽  
Yannick Savoy
Keyword(s):  
Unstructured Grids ◽  
Mesh Adaptation ◽  
Computational Time ◽  
A Posteriori ◽  
Parallel Solution ◽  
Flow Simulations ◽  
Grid Adaption ◽  
Solution Accuracy ◽  
2D And 3D ◽  
Time Grid

The aim of this paper is to discuss efficient adaptive parallel solution techniques on unstructured 2D and 3D meshes. We concentrate on the aspect of parallel a posteriori mesh adaptation. One of the main advantages of unstructured grids is their capability to adapt dynamically by localised refinement and derefinement during the calculation to enhance the solution accuracy and to optimise the computational time. Grid adaption also involves optimisation of the grid quality, which will be described here for both structural and geometrical optimisation.

Numerical Analysis of Axisymmetric Nozzle Aerodynamic Characteristics

2012 ◽  
Vol 184-185 ◽  
pp. 324-327 ◽  
Author(s):  
Ping Wang ◽  
Xue Shan Liu ◽  
Yuan Da Wang ◽  
Xiao Kun Wang
Keyword(s):  
Numerical Analysis ◽  
Boundary Conditions ◽  
Test Data ◽  
Aerodynamic Characteristics ◽  
Flow Fields ◽  
Numerical Results ◽  
Axisymmetric Nozzle ◽  
Model Application ◽  
Grid Adaption ◽  
Abstract Method

Abstract: Method of CFD is used to simulate flow fields for a certain Axisymmetric nozzle, The paper describes the grid adaption, boundary conditions determination as well as RNG model application, and analyzes the nozzle aerodynamic characteristics. The numerical results match well with test data.

Grid Transformation and Adaption Techniques Applied in the Analysis of Cavitated Journal Bearings

1990 ◽  
Vol 112 (1) ◽  
pp. 52-59 ◽  
Author(s):  
D. Vijayaraghavan ◽  
T. G. Keith
Keyword(s):  
Coordinate System ◽  
Journal Bearing ◽  
Numerical Procedure ◽  
Computer Time ◽  
Journal Bearings ◽  
Second Order ◽  
Film Rupture ◽  
Transformation Procedure ◽  
Grid Adaption ◽  
Induced Flow

An existing cavitation algorithm (a numerical procedure that automatically predicts film rupture and reformation in bearings) is modified in this paper. Second order upwinding is used to difference the shear induced flow terms in the cavitated region. A grid transformation procedure using a body fitted coordinate system and grid adaption techniques are applied to the algorithm. Four statically loaded finite journal bearing cases are analyzed. The results are compared with the results obtained using a conventional grid. The advantage of these methods is demonstrated by obtaining equal or better accuracy with a coarser grid and by the consumption of smaller amounts of computer time.

Sign in / Sign up

Export Citation Format

Share Document