I have a question about SWAN wave model, I tried to ask it at the SWAN mailing list, but with no luck, so I'm asking here.
First of all I have to admit I'm not a professional SWAN user. All the knowledge of SWAN I have I have received from the user manual and google. Neither am I an oceanologist, so I can't say I really understand what the model does. However, I need to use it.
I used GridBuilder to generate the grid, that is why I'm using curvilinear grids (the grid is actually a rectnagle, but GridBuilder generates only curvilinear grids when exporting for SWAN).
I'm trying to compute wave properties using this task:
PROJECT 'p1' 'r1' SET NAUTICAL MODE DYN TWODimensional PROP BSBT CGRID CURVILINEAR 90 86 EXC -9999 CIRCLE 10 0.03 0.55 40 READGRID COORDINATES 1 'data.grd' 4 0 0 FREE INPGRID BOTTOM CURVILINEAR 0 0 90 86 EXC -9999 READINP BOTTOM 1 'data.bot' 4 0 FREE GEN2 WIND vel=20 dir=270 BLOCK 'COMPGRID' NOHEADER 'results.mat' LAY 3 XP YP BOTLEV WIND HSIG HSWELL VEL WATLEV DEPTH PER WLEN OUT 20200101.000000 5 MIN COMPUTE NONSTAT 20200101.000000 10 SEC 20200101.003000 STOP
If I understand the syntax correctly, then SWAN should compute wave propagation during 2.30 hours using wind with speed 20 m/s that blows from the West. However, when I check the results in MATLAB, I see that HSIG is about 0.0012 or something like that. This looks strange to me, since I'd expect waves to be much higher when the wind speed is 20 m/s which is a gale wind.
I have computed the same properties for a whole day and the results are almost equal. These are the lines of the second task that differ from the first one:
BLOCK 'COMPGRID' NOHEADER 'results.mat' LAY 3 XP YP BOTLEV WIND HSIG HSWELL WATLEV VEL DEPTH PER WLEN OUT 20200101.000000 30 MIN COMPUTE NONSTAT 20200101.000000 10 MIN 20200102.000000
However, period is about 2.0126634 and wave length is 5.0730591. This parameter combination looks strange to me.
Did I miss something while composing the task? Thank you for help in advance.