|
[Sponsors] |
January 19, 2022, 08:42 |
Upwind Scheme Steady State Problem
|
#1 |
New Member
ugurtan
Join Date: May 2020
Location: Munich, Germany
Posts: 19
Rep Power: 6 |
Dear SU2 users,
I am using SU2 7.1.1 for an external flow problem 0.5 Mach at sea level. I have obtained steady results with decreasing relative residuals up to 4 levels by JST central scheme with artificial viscosity. However, steady state convergence is not possible for upwind schemes (I am mostly trying AUSMPLUSUP2 btw). Although I have obtained converged aerodynamic coefficients and stable flow contours, residuals stall after one order of reduction from farfield initial condition. I have read Venkatakrishnan's paper (Convergence to Steady State Solutions of the Euler Equations on Unstructured Grids with Limiters) and I came to this conclusion: The limiters are wiggling i.e. the cause of stalling residuals. As the coefficient of Venkatakrishnan decreases, residuals are getting better but it is still less than 2 order of magnitude. I have some thoughts which I listed below but it would be pretty good to hear some advices from you! 1) I have prepared a fully structured mesh to check the effect of limiters on mesh type, but I am not sure if it is gonna work. 2) I have tried to use LIMITER_ITER to freeze limiter values after oscillations around quasi-converged aerodynamic coefficients starts but solution crashed. 3) I need to understand the effect of VENKAT_LIMITER_COEFF. In his paper, Venkatakrishnan achieves better residuals by increasing coefficient K whereas I have achieved better stability with decreasing VENKAT_LIMITER_COEFF in SU2. It would be nice if there is any document/paper etc. to get information about the VENKAT_LIMITER_COEFF in SU2. 4) Beyond all, I want to perform a DES analysis in SU2. In my opinion, JST is not a good choice with its diffusivity. For that reason, I wanted to use an upwind scheme in DES study but I need to be sure that the effect of wiggling limiters is minimal during data collecting stage in DES. Nevertheless, my DES experience is limited so I want you to know that I am open to read different views, comments, paper advices, documents etc. Thank you very much for your patience and your time! |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Time-accurate solution restart from steady state solution | jyotir | SU2 | 6 | December 8, 2021 08:34 |
Domain Reference Pressure and mass flow inlet boundary | AdidaKK | CFX | 75 | August 20, 2018 05:37 |
Upwind scheme - convergence problem | MissCFD | CFX | 1 | April 1, 2015 04:23 |
Steady State 2 phase problem | fivos | FLUENT | 0 | April 27, 2009 16:34 |
Time discretisation scheme for steady state case | Andrey | CFX | 7 | September 16, 2008 03:40 |