Hello,
For a research project, I need to simulate wind waves over a lake. We use 2 spatial references, the lake in the globality and the site of the projet.
First one, we calculate wind velocities and estimate wave heights in deep water (JONSWAP).
Data:
Fetch = 11km
U10 = 19 m/s
Result:
Hs = between 1 and 1.1 m
Tp = 3.7 s
In other part, we simulate wind waves with Mike21SW (FM).
Data:
U10 = 19 m/s
Direction = 225 °
Parameters:
Quasi-stationary
Directionally decoupled parametric formulation (16 directions)
No wave Breaking
No diffraction
Bottom friction Nikuradse roughness kn 0.04
Initial conditions SPM1973 Deep Water
Depth for the site around 20 m
Result:
The first approximations with JONSWAP seem correct (near viky2507’s estimation) http://forum.mikepoweredbydhi.com/index.php/topic,3109.0.html
The initial conditions give results like JONSWAP method. Hs in the site around 1.04 .
--> SEE ATTACHMENTS http://www.servimg.com/view/17596096/75
[img width=200 height=150]http://i97.servimg.com/u/f97/17/59/60/96/initia10.png[/img]
But we obtain different results at the end of the simulation. Hs for the site around 0.75 .
--> SEE ATTACHMENTS http://www.servimg.com/view/17596096/74
[img]http://i97.servimg.com/u/f97/17/59/60/96/th/result10.jpg[/img]
Why do we obtain different results with JONSWAP and Mike21SW ?
I’m not sure if these lower waves are caused by the lake’s geometry and wave’s propagation around the site. Do you think I can use this lower waves?
If i use wave breaking, the results are significaly lower (Hs for site around 0.4).
The formulation « Directionally decoupled parametric » is it correct to estimate the waves for the site (spatial scale is less than ~10-50 km) ? http://forum.mikepoweredbydhi.com/index.php/topic,2533.msg5999.html#msg5999
Thanks a lot for your suggest
I need your answer as soon as possible.
