Unstructured mesh methods for the solution of the unsteady compressible flow equations with moving boundary components

2007 ◽  
Vol 365 (1859) ◽  
pp. 2531-2552 ◽  
Author(s):  
Oubay Hassan ◽  
Kenneth Morgan ◽  
Nigel Weatherill
Keyword(s):  
Compressible Flows ◽  
Unstructured Mesh ◽  
Moving Boundary ◽  
Implicit Time ◽  
Flow Equations ◽  
Time Stepping ◽  
Ale Formulation ◽  
Dual Time Stepping ◽  
Flow Features ◽  
Viscous Compressible Flows

A review of a procedure for the simulation of time-dependent, inviscid and turbulent viscous, compressible flows involving geometries that change in time is presented. The adopted discretization technique employs unstructured meshes and both explicit and implicit time-stepping schemes. A dual time-stepping procedure and an ALE formulation enable flows involving moving boundary components to be included. Techniques that have been developed to maintain the validity of the unstructured mesh and to allow for the capture of moving flow features are also reviewed. Using the in-house developed techniques, some examples are included to demonstrate the use of the approach for the simulation of a number of flows of practical industrial interest.

scholarly journals Numerical Simulation of Unsteady Channel Flow with a Moving Indentation

2019 ◽  
Vol 128 ◽  
pp. 10010
Author(s):  
C R Sonawane ◽  
Y B More ◽  
Anand Pandey
Keyword(s):  
Channel Flow ◽  
Moving Boundary ◽  
Weighted Least Squares ◽  
Riemann Solver ◽  
Complex Flow ◽  
Flowing Fluid ◽  
Ale Formulation ◽  
Flow Features ◽  
Flow Phenomena ◽  
Unsteady Channel Flow

The FSI problem - unsteady channel flow with a moving indentation problem, which represents flow features of oscillating stenosis of a blood vessel, is numerically simulated. The flow inside the channel with moving boundary results in transient and complex flow phenomena mainly due to the interaction between the moving boundary and the flowing fluid. In this paper, an accurate Harten Lax and van Leer with contact for artificial compressibility Riemann solver have been used for flow computation. The Riemann solver is modified to incorporate Arbitrarily Lagrangian-Eulerian (ALE) formulation in order to take care of mesh movement in the computation, where radial basis function is used for dynamically moving the mesh. Higher order accuracy over unstructured meshes is achieved using quadratic solution reconstruction based on solution dependent weighted least squares (SDWLS). The present numerical scheme is validated here and the numerical results are found to agree with experimental results reported in literature.

scholarly journals Transonic Turbomachinery Calculations Using a Hybrid Structured-Unstructured Grid Method

1994 ◽  
Author(s):  
Scott M. Richardson
Keyword(s):  
Unstructured Grid ◽  
Unstructured Mesh ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Grid Method ◽  
Navier Stokes ◽  
Flow Equations ◽  
Transonic Compressor ◽  
Flow Features ◽  
Grid Points

A method is presented for solving the two-dimensional Navier-Stokes equations on a solution-adaptive grid of both structured and unstructured meshes. Flow near airfoil surfaces is modeled using an implicit finite difference algorithm on a structured O-type mesh. The flow equations in the blade passages are written in a cell-vertex finite volume formulation and are solved on an unstructured mesh using a Runge-Kutta explicit algorithm. Both the structured and unstructured grid also include solution dependent adaptation to allow resolution of flow features with a minimum of grid points. The structured mesh divides to locally add grid lines, while the unstructured mesh allows the addition or removal of individual cells. An overlapping interface region is used to conservatively communicate flow variable information between the two grids. The quasi-three-dimensional effects of streamtube contraction and radius change are included to allow calculation of modern turbomachine designs. A study is included to determine the effect on cacade parameters of inclusion of viscous terms in the solution of the flow equations in the unstructured domain. Quasi-three-dimensional computations of flow through a transonic compressor and turbine cascade are compared with experimental data.

Unsteady Rotor/Stator Interaction: An Improved Unstructured Approach

2001 ◽  
Author(s):  
P. Adami ◽  
E. Belardini ◽  
F. Martelli ◽  
V. Michelassi
Keyword(s):  
Implicit Time ◽  
Finite Volume Scheme ◽  
Turbine Stage ◽  
Krylov Method ◽  
Time Stepping ◽  
Steady Stage ◽  
Dual Time Stepping ◽  
Rotor Stator Interaction ◽  
Time Marching ◽  
Aero Engines

A full-3D unstructured solver based on an upwind TVD finite volume scheme is developed and applied to the simulation of an unsteady turbine stage. Two different approaches are considered for the time accurate inviscid simulation of the unsteady stator/rotor interaction. The first consists of a classical explicit time accurate multi-step Runge-Kutta scheme. The second is based on a dual-time stepping strategy, which exploits the implicit time-marching Newton-Krylov method. In this case the linear solver of the implicit scheme consists of a preconditioned GMRES and ILU(0) incomplete factorisation. Both the explicit and implicit approaches are designed to run on parallel cluster of workstations. The development of the numerical strategy is discussed with particular concern on the validation of the unsteady model through a comparison against experiments, NISRE approach and a 3D steady stage computation. The results compare favourably with a set of time averaged and unsteady experimental data available for the turbine stage under investigation, which is representative of a wide class of aero-engines. Both the accuracy of the solver and the capability of the computational model are discussed.

Improvements to a dual-time-stepping method for computating unsteady flows

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1548-1550 ◽  
Author(s):  
S. DeRango ◽  
D. W. Zingg
Keyword(s):  
Unsteady Flows ◽  
Time Stepping ◽  
Dual Time Stepping
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