Fluid relaxation doesn't perform well for opening bcs

Xiangyu-Hu / SPHinXsys

SPHinXsys provides C++ APIs for engineering simulation and optimization. It aims at complex systems driven by fluid, structure, multi-body dynamics and beyond. The multi-physics library is based on a unique and unified computational framework by which strong coupling has been achieved for all involved physics.

https://xiangyu-hu.github.io/SPHinXsys/

Apache License 2.0

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Fluid relaxation doesn't perform well for opening bcs #639

Open WeiyiVirtonomy opened 3 months ago

WeiyiVirtonomy commented 3 months ago

Describe the bug The inflow region has velocity and pressure singularities if the fluid particles are relaxed. E.g. T-shaped pipe flow:

This is within the inflow region, where the velocity is prescribed. Weirdly, the velocity within this region is not exactly parabolic. The simulation can still go on with the parameters used in test_2d_T_shaped_pipe, but in some cases, it can fail after several steps.

To Reproduce Add relaxation of fluid in test_2d_T_shaped_pipe.

WeiyiVirtonomy commented 3 months ago

@DongWuTUM I reported this issue