Hello Richard,
Could you please explain me, how CAESAR II is calculating the Natural frequency of the pipe (Modal analysis) to decide the support span and its functions.

I have tried manually with Piping Code: DNV-RP-D101, October 2008. (A17.2 VIV Checkout procedure, page no 31/42). DNV code formula giving the frequency is less than the CAESAR II value (verson 5.10 with the build 090206), like the variation is +5% without medium & +3.5% with the medium . It means the CAESAR II is giving higher value than the DNV code value.

FYI:-
I have done frequency calculation with the fixed constant a=22.4 (Fixed –Fixed),
Condition: Horizontal pipe having length L=4.5m & size:2 Inch with SCH160 and fixed at both end (Fixed-Fixed).

Could you please send me the formula, which is using in CAESAR II to calculate Natural frequency (Modal analysis)

Thanks,
R Seeralan