# \#compressible **URL:** https://pyfr.discourse.group/tag/compressible/4.md [Latest](https://pyfr.discourse.group/latest.md) · [Categories](https://pyfr.discourse.group/categories.md) · [Tags](https://pyfr.discourse.group/tags.md) --- ## [Dual time stepping for high Mach flows](https://pyfr.discourse.group/t/dual-time-stepping-for-high-mach-flows/1244)
**Author:** [@Olaf](https://pyfr.discourse.group/u/Olaf)\ **Replies:** 3\ **Last updated:** [7 April 2025 18:42 UTC](https://pyfr.discourse.group/t/dual-time-stepping-for-high-mach-flows/1244 "2025-04-07T18:42:02Z")
Hello. I am trying to use dual time stepping for a compressible flow simulation (M = 5) but I always get the same error no matter what mesh I use. I have tried using the test example but I get the same error over and ov… --- ## [Entropy filtering and adaptive time stepping](https://pyfr.discourse.group/t/entropy-filtering-and-adaptive-time-stepping/1115)
**Author:** [@Frankx9](https://pyfr.discourse.group/u/Frankx9)\ **Replies:** 2\ **Last updated:** [30 June 2024 17:32 UTC](https://pyfr.discourse.group/t/entropy-filtering-and-adaptive-time-stepping/1115 "2024-06-30T17:32:31Z")
Hello, is there a particular reason for which entropy filtering is not compatible with adaptive time stepping? Best regards --- ## [Entropy filter - point set combination](https://pyfr.discourse.group/t/entropy-filter-point-set-combination/1107)
**Author:** [@Frankx9](https://pyfr.discourse.group/u/Frankx9)\ **Replies:** 7\ **Last updated:** [11 June 2024 23:17 UTC](https://pyfr.discourse.group/t/entropy-filter-point-set-combination/1107 "2024-06-11T23:17:23Z")
Hello, I was trying to use the entropy filtering but I don’t understand why this point set combination is not valid \[solver-interfaces-quad\] flux-pts = gauss-legendre-lobatto \[solver-interfaces-tri\] flux-pts = alpha-… --- ## [About specific heat Cp and cpTref](https://pyfr.discourse.group/t/about-specific-heat-cp-and-cptref/1099)
**Author:** [@wgbb](https://pyfr.discourse.group/u/wgbb)\ **Replies:** 2\ **Last updated:** [31 May 2024 01:25 UTC](https://pyfr.discourse.group/t/about-specific-heat-cp-and-cptref/1099 "2024-05-31T01:25:41Z")
Hello, everyone. Can I ask you a question about specific heat Cp? When I want to use isothermal wall surfaces I find that Cp confuses me a bit as I am using dimensionless to flow parameters and I don’t understand how C… --- ## [PyFR boundary conditions for turbomachinery](https://pyfr.discourse.group/t/pyfr-boundary-conditions-for-turbomachinery/961)
**Author:** [@Frankx9](https://pyfr.discourse.group/u/Frankx9)\ **Replies:** 53\ **Last updated:** [28 January 2024 14:22 UTC](https://pyfr.discourse.group/t/pyfr-boundary-conditions-for-turbomachinery/961 "2024-01-28T14:22:52Z")
Hello, I’m running a simulation in pyFR but I noticed that the results are not correct due to the fact that the outlet boundary condition (char-riem-inv) is not respected. Here is my .ini file regarding outlet u2 = 20… --- ## [How to speed up a compressible T106C simulation](https://pyfr.discourse.group/t/how-to-speed-up-a-compressible-t106c-simulation/776)
**Author:** [@ManuSaiVenkataRatnam](https://pyfr.discourse.group/u/ManuSaiVenkataRatnam)\ **Replies:** 5\ **Last updated:** [27 October 2023 04:08 UTC](https://pyfr.discourse.group/t/how-to-speed-up-a-compressible-t106c-simulation/776 "2023-10-27T04:08:51Z")
Hello Team Pyfr, This is in regards to my thesis work. I have to do T106C test case for my work, but the simulation is taking more time for a warm up of 100 time units of order 1. following are some initial test runs… --- ## [Transonic, supersonic cases](https://pyfr.discourse.group/t/transonic-supersonic-cases/856)
**Author:** [@Zhenyang](https://pyfr.discourse.group/u/Zhenyang)\ **Replies:** 1\ **Last updated:** [26 June 2023 19:33 UTC](https://pyfr.discourse.group/t/transonic-supersonic-cases/856 "2023-06-26T19:33:57Z")
Hi, I wonder if community has some publications about transonic or supersonic applications with PyFR? How well does it work in general? Regards, Zhenyang --- ## [Non-dimensionalized sutherland law](https://pyfr.discourse.group/t/non-dimensionalized-sutherland-law/695)
**Author:** [@YoonSuKyung](https://pyfr.discourse.group/u/YoonSuKyung)\ **Replies:** 12\ **Last updated:** [2 June 2023 06:31 UTC](https://pyfr.discourse.group/t/non-dimensionalized-sutherland-law/695 "2023-06-02T06:31:56Z")
Hi, i’m Sukyung Yoon I want to compare the compressible and incompressible flow field for the same Reynolds number condition. Question1\> I want to simulate the Reynolds number 15,000 conditions. Can it be said that t… --- ## [Incoming flow with an Angle of attack](https://pyfr.discourse.group/t/incoming-flow-with-an-angle-of-attack/799)
**Author:** [@fei](https://pyfr.discourse.group/u/fei)\ **Replies:** 3\ **Last updated:** [19 April 2023 07:32 UTC](https://pyfr.discourse.group/t/incoming-flow-with-an-angle-of-attack/799 "2023-04-19T07:32:57Z")
Hello, when I simulate the supersonic case with an Angle of attack, Assume freestream velocity is U, angle of attack is the theta, then the inflow condition is u = Ucos(theta), v = Usin(theta)? And I try this operation, … --- ## [How to configure Sutherland's Law](https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701)
**Author:** [@YoonSuKyung](https://pyfr.discourse.group/u/YoonSuKyung)\ **Replies:** 1\ **Last updated:** [5 April 2023 08:48 UTC](https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701 "2023-04-05T08:48:10Z")
How should variables related to sutherland’s law(mu and cpTref, cpTs) be defined to use normalized values(P=1, rho=1, u=1 ,)? Does the temperature not have a unit? --- ## [Some questions about sutherland laws](https://pyfr.discourse.group/t/some-questions-about-sutherland-laws/778)
**Author:** [@fei](https://pyfr.discourse.group/u/fei)\ **Replies:** 6\ **Last updated:** [27 March 2023 20:00 UTC](https://pyfr.discourse.group/t/some-questions-about-sutherland-laws/778 "2023-03-27T20:00:56Z")
Hello, I run the case at high Mach and Reynolds number, such as 3 mach and Reynolds 1e4. When I don’t use the viscosity law, it will immediately break with Nanh. But when I use the sutherland’s law, it will run for a w… --- ## [Scalability and linearised NS solver](https://pyfr.discourse.group/t/scalability-and-linearised-ns-solver/464)
**Author:** [@Zhenyang](https://pyfr.discourse.group/u/Zhenyang)\ **Replies:** 5\ **Last updated:** [18 August 2021 15:56 UTC](https://pyfr.discourse.group/t/scalability-and-linearised-ns-solver/464 "2021-08-18T15:56:41Z")
Hi, I am interested in the optimal grid points for each CPU/GPU core since I am going to run some large scale cases. Although it could be different from machines, it would be nice to have some basic idea before doing te…