About CFL number !

January 8, 2008, 09:26

The CFL number is function of three parameters, it's found for controller that the scheme is stable. The choice of the CFL infect the space time. In case of Roe scheme, the scheme is stable for 0 < CFL <=1. So far I think that all fine. In some meshes there will be no stable for value lower than 1, but they still need to be small, and even if it was in this interval was not necessarily stability

Could you explain it ! thanks

January 19, 2008, 23:29

Are you using FVM code or finite difference code. Low courant number is not a stability requirement for FVM codes.

Usman

January 21, 2008, 10:09

That's not correct. A low CFL number is not a stability requirement for implicit schemes, but an explicit FV scheme will still be CFL-limited.

January 23, 2008, 19:16

ag is right! Sorry about that. For some reason i mixed up FV with implicit scheme.

Usman

January 8, 2008, 09:26	About CFL number !	#1
emca Guest Posts: n/a	The CFL number is function of three parameters, it's found for controller that the scheme is stable. The choice of the CFL infect the space time. In case of Roe scheme, the scheme is stable for 0 < CFL <=1. So far I think that all fine. In some meshes there will be no stable for value lower than 1, but they still need to be small, and even if it was in this interval was not necessarily stability Could you explain it ! thanks

January 19, 2008, 23:29	Re: About CFL number !	#2
Usman Guest Posts: n/a	Are you using FVM code or finite difference code. Low courant number is not a stability requirement for FVM codes. Usman

January 21, 2008, 10:09	Re: About CFL number !	#3
ag Guest Posts: n/a	That's not correct. A low CFL number is not a stability requirement for implicit schemes, but an explicit FV scheme will still be CFL-limited.

January 23, 2008, 19:16	Re: About CFL number !	#4
Usman Guest Posts: n/a	ag is right! Sorry about that. For some reason i mixed up FV with implicit scheme. Usman

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