Learning Forum

[NVN NAMMA]

5.2.2.1. Stability/Time Response Specific Options

 

The Tube Drag Coefficients and Scale Factor for Model Test Simulation options apply to all Morison (TUBE and STUB) elements within your Geometry. These options affect only Stability and Time Response analyses; they are not used in Hydrodynamic Diffraction or Frequency Statistical analyses. 

 

I have a question. Does AQWA consider morison elements (more specifically, a freely suspended pipe from the floating structure) in its diffraction analysis?. How the two structural motions are coupled

[Mike Pettit]

Hello,

Aqwa does consider Morison elements in the Hydrodynamic Diffraction analysis if you switch on the 'Linearized Morison Drag' option in the Analysis Settings. For this to work, you also need to define an Irregular Wave spectrum in the Hydrodynamic Diffraction system (only possible while the above option is turned on).

The Aqwa solver uses the wave spectrum to linearize the drag term of the Morison equation (see 6.4. Morison Drag Linearization) and includes additional terms in the equation of motion (see 4.5. Response Amplitude Operators with Additional Input). The RAO calculation is iterative in this case, to account for the relative velocity between the structure and the fluid and its effect on the drag term.

I hope this helps.

Mike