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Auteurs principaux: Roenby, Johan, Aliyar, Sithik, Bredmose, Henrik
Format: Preprint
Publié: 2023
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Accès en ligne:https://arxiv.org/abs/2310.01199
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author Roenby, Johan
Aliyar, Sithik
Bredmose, Henrik
author_facet Roenby, Johan
Aliyar, Sithik
Bredmose, Henrik
contents We present a non-iterative algorithm, FloatStepper, for coupling the motion of a rigid body and an incompressible fluid in computational fluid dynamics (CFD) simulations. The purpose of the algorithm is to remove the so-called added mass instability problem, which may arise when a light floating body interacts with a heavy fluid. The idea underlying the presented coupling method is to precede every computational time step by a series of prescribed probe body motions in which the fluid response is determined, thus revealing the decomposition of the net force and torque into two components: 1) An added mass contribution proportional to the instantaneous body acceleration, and 2) all other forces and torques. The algorithm is implemented and released as an open source extension module to the widely used CFD toolbox, OpenFOAM, as an alternative to the existing body motion solvers. The accuracy of the algorithm is investigated with several single-phase and two-phase flow benchmark cases. The benchmarks demonstrate excellent stability properties, allowing simulations even with massless bodies. They also highlight aspects of the implementation, such as the mesh motion method, where more work is needed to further enhance the flexibility and predictive capabilities of the code.
format Preprint
id arxiv_https___arxiv_org_abs_2310_01199
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A robust algorithm for computational floating body dynamics
Roenby, Johan
Aliyar, Sithik
Bredmose, Henrik
Fluid Dynamics
We present a non-iterative algorithm, FloatStepper, for coupling the motion of a rigid body and an incompressible fluid in computational fluid dynamics (CFD) simulations. The purpose of the algorithm is to remove the so-called added mass instability problem, which may arise when a light floating body interacts with a heavy fluid. The idea underlying the presented coupling method is to precede every computational time step by a series of prescribed probe body motions in which the fluid response is determined, thus revealing the decomposition of the net force and torque into two components: 1) An added mass contribution proportional to the instantaneous body acceleration, and 2) all other forces and torques. The algorithm is implemented and released as an open source extension module to the widely used CFD toolbox, OpenFOAM, as an alternative to the existing body motion solvers. The accuracy of the algorithm is investigated with several single-phase and two-phase flow benchmark cases. The benchmarks demonstrate excellent stability properties, allowing simulations even with massless bodies. They also highlight aspects of the implementation, such as the mesh motion method, where more work is needed to further enhance the flexibility and predictive capabilities of the code.
title A robust algorithm for computational floating body dynamics
topic Fluid Dynamics
url https://arxiv.org/abs/2310.01199