2nd-order wave kinematics

[JArtalG]

In the UMaineSemi model, 2nd-order wave kinematics flags are set to True. Given that no strip-theory model is defined in this model, these flags have no effect in the simulation, but their calculation demands large time and computational resources (specially in long simulations).

IEA-15-240-RWT/OpenFAST/IEA-15-240-RWT-UMaineSemi/IEA-15-240-RWT-UMaineSemi_SeaState.dat

Lines 35 to 36 in 31ec0e3

	True WvDiffQTF - Full difference-frequency 2nd-order wave kinematics (flag)
	True WvSumQTF - Full summation-frequency 2nd-order wave kinematics (flag)

If no strip-theory model is planed to be developed, is better to switch these flags to False, to increase the efficiency of the simulations.

[luwang00]

@JArtalG Yes, you are correct. With the way the model is currently set up, 2nd-order wave kinematics have no effect and can be turned off for speed. We are currently working on updating the HydroDyn model with strip-theory members primarily for computing drag force on the structure. Even then, with the inclusion of up to 2nd-order potential-flow model, 2nd-order wave kinematics have little impact and can be turned off.

[JArtalG]

Dear Lu, thank you very much for you detailed and prompt response, really looking forward for that Morison model! is it being defined based on any of the tank tests of the OC projects?

[luwang00]

Yes, it is based on a recently concluded OC study. We are hoping the new strip-theory drag model will perform a bit better compared to the previous quadratic damping coefficients. Still, it is not possible to have one set of coefficients that work for all sea states/conditions, so some fine tunning would be required by the modeler. We will try to get the model updated shortly.

[JArtalG]

Sounds great, thanks Lu!