# References for double shock case

**URL:** <https://pyfr.discourse.group/t/references-for-double-shock-case/539>\
**Category:** General\
**Created:** [7 February 2022 12:44 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539 "2022-02-07T12:44:27Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![jian](https://avatars.discourse-cdn.com/v4/letter/j/7ba0ec/32.png) [@jian](https://pyfr.discourse.group/u/jian)\
**Post date:** [7 February 2022 12:44 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539/1 "2022-02-07T12:44:27Z")

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Hello, I want to find the concrete introduction of double shock calculation example. Could you tell me which paper has this introduction?

Best regards

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**Author:** ![jian](https://avatars.discourse-cdn.com/v4/letter/j/7ba0ec/32.png) [@jian](https://pyfr.discourse.group/u/jian)\
**Post date:** [7 February 2022 12:46 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539/2 "2022-02-07T12:46:50Z")

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Hello, I want to find the concrete introduction of double shock calculation example. Do you know which article contains the double shock example in this link?

> [@Is PyFR suitable for supersonic cases?](https://pyfr.discourse.group/t/is-pyfr-suitable-for-supersonic-cases/123):
>
> Dear all, I've tried a few of supersonic cases and failed each time. And there's no supersonic cases in published posts. I'm wondering if PyFR is suitable for supersonic cases in normal working condition? Best regards, Ray

Best regards

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**Author:** ![WillT](https://avatars.discourse-cdn.com/v4/letter/w/bc79bd/32.png) [@WillT](https://pyfr.discourse.group/u/WillT)\
**Post date:** [7 February 2022 13:21 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539/3 "2022-02-07T13:21:27Z")

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I’m not sure which case exactly you mean, do you mean the 2D Reimann problems? If so below are some links?

[https://doi.org/10.1007/BF00251604](https://doi.org/10.1007/BF00251604)  
[https://doi.org/10.1137/S1064827595291819](https://doi.org/10.1137/S1064827595291819)

Or do you perhaps mean the double mach reflection case? If so the following are useful

[https://doi.org/10.1016/0021-9991(84)90142-6](https://doi.org/10.1016/0021-9991(84)90142-6)  
[https://doi.org/10.1016/j.compfluid.2016.04.008](https://doi.org/10.1016/j.compfluid.2016.04.008)  
[https://doi.org/10.1007/s10915-018-0803-x](https://doi.org/10.1007/s10915-018-0803-x)

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<div class="post-metadata">

**Author:** ![jian](https://avatars.discourse-cdn.com/v4/letter/j/7ba0ec/32.png) [@jian](https://pyfr.discourse.group/u/jian)\
**Post date:** [7 February 2022 13:34 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539/4 "2022-02-07T13:34:14Z")

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Thanks a lot. I mean double shock case in that link. The density contour is shown below.

 ![LKZ`)32YU)DP7NA_RIV7310](https://global.discourse-cdn.com/free1/uploads/pyfr/original/1X/00f6231c538385f24fc955c858ebac3ffe5c50c8.jpeg)

Best regards

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<div class="post-metadata">

**Author:** ![WillT](https://avatars.discourse-cdn.com/v4/letter/w/bc79bd/32.png) [@WillT](https://pyfr.discourse.group/u/WillT)\
**Post date:** [7 February 2022 13:44 UTC](https://pyfr.discourse.group/t/references-for-double-shock-case/539/5 "2022-02-07T13:44:43Z")

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Ah ok,

I can’t think of a paper that talks about it, but I know Paul has it in his book [https://doi.org/10.1017/CBO9781139872010](https://doi.org/10.1017/CBO9781139872010)

The best way I have found to use this case is set the inflow mach number and the outflow mach number and then use oblique shock relations to find the exact angle and length of the slope required for the first reflection to exactly hit the right-most corner of the slope. This should mean that there isn’t a second reflection and if there is one is means your scheme is off in some way, ie too much diffusion.