[adikaagas]

Currently im trying to solve 2D Fluid-Structure Interaction on a water tank using time domain analysis with Predictor-Corrector Method developed by Liu and Sakai (2002).

I was able to simulate vertical displacement of Fluid domain that governs by Laplace equation and Boundary Element Method, but struggling on find a convergence value of 𝜕𝜑╱𝜕𝑡 on Structure Domain that will be further used for a pressure input (external force) on Finite Element Analysis of Dynamics Structure Equation. ({xdd} [M] + {x} [K] = {F} )

At the beginning of time step, the value of 𝜕𝜑╱𝜕𝑡 is stable and converged. but somehow the value of 𝜕𝜑╱𝜕𝑡 will be NaN because of there is no inflection point.

Does my formulation to find 𝜕𝜑╱𝜕𝑡 value on structure Domain is correct using modified of motion equation on Step 4 or my Predictor Corrector scheme is wrong? (.docx attachment)

I've been debugging for over 1 month and still cant solve and my scholarship is running out, I'm very appreciate for those who wants to help me any little help will be very important for me.

[adikaagas]

Here's my example of 𝜕𝜑╱𝜕t convergence problems. (Attachment .jpg)