Wave Pressure

andi_tri

Hi all,
I make simulation on wave generation and propagation also compare with experiment result. for wave elevation is good agreement between experiment but for wave pressure there is still big different with experiment I use deltasph 0,1 and 0,2 but still not help much. is there any suggestion for increase accuracy?

Regards

https://drive.google.com/open?id=0B5z6dgCwVIC0QndGS0lua2xfYms
https://drive.google.com/open?id=0B5z6dgCwVIC0VmluWGl3Wm05a1k
https://drive.google.com/open?id=0B5z6dgCwVIC0SHpXbW1CODRPeEE
https://drive.google.com/open?id=0B5z6dgCwVIC0RDA4cFQtT2RFWE0
https://drive.google.com/open?id=0B5z6dgCwVIC0RzNPWnp4eUxiVXc

amir

Hi
1- The domain length seems to be very long, that the wave decay occurs.
2- Instead of artificial viscosity, use SPS.
3- When calculating pressure at a point, you should consider ONLY fluid particles and omit the solid particles.
4- Use CFL number equal to 0.12 or 0.1
5- Please provide the source of the experimental data.

andi_tri

will try your suggestion, I know domain longer than suggestion in guide, that's why i'm not use all suggestion in guide and try varying several parameter and work for wave elevation but for pressure still have discrepancy. sorry i made mistake for points pressure

Points of pressure
27 0.2 0.75

https://drive.google.com/open?id=0B5z6dgCwVIC0eEdqNUhNZm1JSUE
https://drive.google.com/open?id=0B5z6dgCwVIC0RWRNZ2F1Vm1uaWs

Regards,

Alex

As explained in the guide and in several testcases:

- DBC conditions generate a gap between fluid and boundary of 1.5*h.
- If you want to compute pressure at a location in the boundary layer, you should move your pressure gauge at 1.5*h inside the fluid.

You can find several PDFs explained this in the testcases:
CaseDambreak_Pressure_Probes.pdf
CaseSloshing_Pressure_Probes.pdf

Regards

andi_tri

Thanks Alex for your response so I must put inside fluid maybe that's problem why I always get discrepancy result.

Best Regards,

Alex

If you create a pressure gauge 1.5*h far from boundary you are not inside fluid!
You will be at the effective boundary layer, and yes close to fluid, but not inside.

Note that you have to use pressure from fluid particles to compute pressure at that point and no pressure from boundary particles, but I assume you already are doing this, right? -onlytype:-all,+fluid.
You only need to follow the examples in CaseDambreak and CaseSloshing

Regards

andi_tri

Yes I use onlytype:-all,+fluid -vars:+press,+vel so in this simulation I want capture pressure in surface. Thanks for your help, will try again and update it if I have better result.

Best Regards,

andi_tri

Alex I have been read

http://www.dual.sphysics.org/index.php/forums1/#/discussion/745/direct-calculate-the-water-pressure-inside-dualsphysicsv4-for-each-time-step

can I change value of -kclimit or -kcdummy to get better result?because those value influence pressure and pressure value getting better than before. now I just change -kclimit value and result better than before.

Regards,