Laminar supersonic compression ramp
Hello, I'm trying to use the compressible flow solver in Nektar++ for a laminar supersonic compression ramp case. I'm using version 4.3.4. After running into issues and digging around in the code a bit, I figured out that the only Riemann solver which includes the viscous fluxes is HLLC. After switching the UpwindType to HLLC, the code runs, but it quits after the second time step. Here is the output of the code: ======================================================================= Initial Conditions: - Field rho: rhoInf - Field rhou: rhoInf * uInf - Field rhov: 0 - Field E: pInf / (Gamma - 1) + 0.5 * rhoInf * uInf * uInf - Field eps: 0 Writing: "ramp_0_0.chk" Steps: 1 Time: 1e-09 CPU Time: 0.922648s Writing: "ramp_0_1.chk" Steps: 2 Time: 2e-09 CPU Time: 0.866426s Fatal : Level 0 assertion violation NaN found during time integration. I tried different time integration schemes to see if that helped, to no avail. Any insights or pointers on what is causing the NaNs? A coarse mesh file and session file are attached. Thanks for your time, James
Hi James, After checking your xml file, I think the shock capturing method is not implemented in the NavierStokesCFE, to which you need to pay attention. Also, I suggest you start with the NonSmooth shock capturing methods, which is perhaps more robust. Best Jian -----原始邮件----- 发件人: "Grisham, James Ray, IV" <james.grisham@mavs.uta.edu> 发送时间: 2016年9月13日 星期二 收件人: "nektar-users@imperial.ac.uk" <nektar-users@imperial.ac.uk> 抄送: 主题: [SPAM] [Nektar-users] Laminar supersonic compression ramp Hello, I'm trying to use the compressible flow solver in Nektar++ for a laminar supersonic compression ramp case. I'm using version 4.3.4. After running into issues and digging around in the code a bit, I figured out that the only Riemann solver which includes the viscous fluxes is HLLC. After switching the UpwindType to HLLC, the code runs, but it quits after the second time step. Here is the output of the code: ======================================================================= Initial Conditions: - Field rho: rhoInf - Field rhou: rhoInf * uInf - Field rhov: 0 - Field E: pInf / (Gamma - 1) + 0.5 * rhoInf * uInf * uInf - Field eps: 0 Writing: "ramp_0_0.chk" Steps: 1 Time: 1e-09 CPU Time: 0.922648s Writing: "ramp_0_1.chk" Steps: 2 Time: 2e-09 CPU Time: 0.866426s Fatal : Level 0 assertion violation NaN found during time integration. I tried different time integration schemes to see if that helped, to no avail. Any insights or pointers on what is causing the NaNs? A coarse mesh file and session file are attached. Thanks for your time, James
Hi Jian, James, One option is that there is a branch, feature/cfs-NS-shock, in which Dirk (the original author of the shock capturing code) added support for the artificial diffusion terms for NS. I suspect it has not been updated in some time, so probably needs master merging in to bring it up to date with 4.3.4. Cheers, Dave
On 13 Sep 2016, at 09:26, Jian Yu <yuj@buaa.edu.cn> wrote:
Hi James,
After checking your xml file, I think the shock capturing method is not implemented in the NavierStokesCFE, to which you need to pay attention. Also, I suggest you start with the NonSmooth shock capturing methods, which is perhaps more robust.
Best
Jian
-----原始邮件----- 发件人: "Grisham, James Ray, IV" <james.grisham@mavs.uta.edu> 发送时间: 2016年9月13日 星期二 收件人: "nektar-users@imperial.ac.uk" <nektar-users@imperial.ac.uk> 抄送: 主题: [SPAM] [Nektar-users] Laminar supersonic compression ramp
Hello,
I'm trying to use the compressible flow solver in Nektar++ for a laminar supersonic compression ramp case. I'm using version 4.3.4. After running into issues and digging around in the code a bit, I figured out that the only Riemann solver which includes the viscous fluxes is HLLC. After switching the UpwindType to HLLC, the code runs, but it quits after the second time step. Here is the output of the code:
======================================================================= Initial Conditions: - Field rho: rhoInf - Field rhou: rhoInf * uInf - Field rhov: 0 - Field E: pInf / (Gamma - 1) + 0.5 * rhoInf * uInf * uInf - Field eps: 0 Writing: "ramp_0_0.chk" Steps: 1 Time: 1e-09 CPU Time: 0.922648s Writing: "ramp_0_1.chk" Steps: 2 Time: 2e-09 CPU Time: 0.866426s
Fatal : Level 0 assertion violation NaN found during time integration.
I tried different time integration schemes to see if that helped, to no avail. Any insights or pointers on what is causing the NaNs?
A coarse mesh file and session file are attached.
Thanks for your time,
James
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-- David Moxey (Research and Teaching Fellow) d.moxey@imperial.ac.uk | www.imperial.ac.uk/people/d.moxey Room 364, Department of Aeronautics, Imperial College London, London, SW7 2AZ, UK.
Jian and Dave, Seems that you are right that the shock capturing isn't implemented for NavierStokesCFE. I'll try without shock capturing first to see how badly I need it. Thanks for your insights. James On Tue, 2016-09-13 at 10:29 +0100, David Moxey wrote:
Hi Jian, James,
One option is that there is a branch, feature/cfs-NS-shock, in which Dirk (the original author of the shock capturing code) added support for the artificial diffusion terms for NS. I suspect it has not been updated in some time, so probably needs master merging in to bring it up to date with 4.3.4.
Cheers,
Dave
On 13 Sep 2016, at 09:26, Jian Yu <yuj@buaa.edu.cn> wrote:
Hi James,
After checking your xml file, I think the shock capturing method is not implemented in the NavierStokesCFE, to which you need to pay attention. Also, I suggest you start with the NonSmooth shock capturing methods, which is perhaps more robust. Best
Jian
-----原始邮件----- 发件人: "Grisham, James Ray, IV" <james.grisham@mavs.uta.edu> 发送时间: 2016年9月13日 星期二 收件人: "nektar-users@imperial.ac.uk" <nektar-users@imperial.ac.uk> 抄送: 主题: [SPAM] [Nektar-users] Laminar supersonic compression ramp
Hello,
I'm trying to use the compressible flow solver in Nektar++ for a laminar supersonic compression ramp case. I'm using version 4.3.4. After running into issues and digging around in the code a bit, I figured out that the only Riemann solver which includes the viscous fluxes is HLLC. After switching the UpwindType to HLLC, the code runs, but it quits after the second time step. Here is the output of the code:
=================================================================== ==== Initial Conditions: - Field rho: rhoInf - Field rhou: rhoInf * uInf - Field rhov: 0 - Field E: pInf / (Gamma - 1) + 0.5 * rhoInf * uInf * uInf - Field eps: 0 Writing: "ramp_0_0.chk" Steps: 1 Time: 1e-09 CPU Time: 0.922648s Writing: "ramp_0_1.chk" Steps: 2 Time: 2e-09 CPU Time: 0.866426s
Fatal : Level 0 assertion violation NaN found during time integration.
I tried different time integration schemes to see if that helped, to no avail. Any insights or pointers on what is causing the NaNs?
A coarse mesh file and session file are attached.
Thanks for your time,
James
_______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users
-- David Moxey (Research and Teaching Fellow) d.moxey@imperial.ac.uk | www.imperial.ac.uk/people/d.moxey
Room 364, Department of Aeronautics, Imperial College London, London, SW7 2AZ, UK.
participants (3)
-
David Moxey
-
Grisham, James Ray, IV
-
Jian Yu