Multi-strip numerical modelling of a riser

  • Last Post 20 November 2018
dan_123 posted this 19 November 2018



I am trying to simulate the response of a long vertical tube subjected to a uniform flow using multi-strip modelling. Basically, my idea is to perform multiple 2D analysis (strips) along the span of the tube. Each strip will give me a local force on the cylinder which, added together, will give the total force and, solving the equation of motion, the complete response of the riser can be estimated. An example of this method can be found here, for example:

or here:

Currently, I can do a 2D vortex-induced vibration modelling of a rigid cylinder subjected to a uniform flow using Fluent and a UDF I wrote. The problem I have is how to implement the multi-strip method in ANSYS. My idea is to model the 3D structure and somehow connect the multiple 2D flow models (strips) along the span of the cylinder. Can anyone give me some guidelines as to how to model this?


Thank you.



rwoolhou posted this 20 November 2018

Not an easy problem, and the model can get very complicated very quickly. 

You currently have a 2d force on a section. In a Mechanical model of the whole riser what happens if you apply that force over the whole length of the unit (I assume you've fixed one/both ends or have some motion limit on the bridge)?