A moving control volume approach to computing hydrodynamic forces and torques on immersed bodies

Nishant Nangia, Hans Johansen, Neelesh A. Patankar, Amneet Pal Singh Bhalla*

*Corresponding author for this work

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We present a moving control volume (CV) approach to computing hydrodynamic forces and torques on complex geometries. The method requires surface and volumetric integrals over a simple and regular Cartesian box that moves with an arbitrary velocity to enclose the body at all times. The moving box is aligned with Cartesian grid faces, which makes the integral evaluation straightforward in an immersed boundary (IB) framework. Discontinuous and noisy derivatives of velocity and pressure at the fluid–structure interface are avoided and far-field (smooth) velocity and pressure information is used. We re-visit the approach to compute hydrodynamic forces and torques through force/torque balance equations in a Lagrangian frame that some of us took in a prior work (Bhalla et al., 2013 [13]). We prove the equivalence of the two approaches for IB methods, thanks to the use of Peskin's delta functions. Both approaches are able to suppress spurious force oscillations and are in excellent agreement, as expected theoretically. Test cases ranging from Stokes to high Reynolds number regimes are considered. We discuss regridding issues for the moving CV method in an adaptive mesh refinement (AMR) context. The proposed moving CV method is not limited to a specific IB method and can also be used, for example, with embedded boundary methods.

Original languageEnglish (US)
Pages (from-to)437-462
Number of pages26
JournalJournal of Computational Physics
Volume347
DOIs
StatePublished - Oct 15 2017

Keywords

  • Adaptive mesh refinement
  • Fictitious domain method
  • Immersed boundary method
  • Lagrange multipliers
  • Reynolds transport theorem
  • Spurious force oscillations

ASJC Scopus subject areas

  • Numerical Analysis
  • Modeling and Simulation
  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)
  • Computer Science Applications
  • Computational Mathematics
  • Applied Mathematics

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