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A data-constrained sharp Immersed Boundary Method for aerospace applications

M. A. Chemak, E. Constant, M. Meldi

TL;DR

This work develops a data-constrained sharp Immersed Boundary Method (IBM) integrated with implicit OpenFOAM solvers to accurately represent wall boundary conditions in aerospace-relevant flows. A Luenberger observer drives a time-dependent source-term framework at ghost cells, enabling Dirichlet/Neumann boundary representations through volume forcing rather than explicit wall values, and ensuring stability across unsteady and compressible regimes. The method is validated on a 2D NACA0012 profile, a 3D supersonic sphere, and a realistic IXV re-entry vehicle, showing robust wall-pressure predictions and favorable accuracy-cost trade-offs, particularly for pressure forces, while viscous/shear predictions require higher grid resolution or gradient-constraining strategies. Limitations include underprediction of wall shear due to non-conservative IBM formulations and absence of detailed near-wall turbulence modeling, which are identified as clear avenues for future enhancements. Overall, the approach offers a portable, efficient, and accurate alternative for preliminary aerospace analyses where high-fidelity wall-resolved simulations are prohibitively expensive.

Abstract

A numerical tool relying on sharp Immersed Boundary Method (IBM) is developed for the analysis of aerospace applications. The method, which is conceived for application using segregated solvers relying on implicit time discretization, uses a Luenberger observer to dynamically update the free coefficients governing the numerical algorithm. This technique improves the accuracy of the method and permits to target the representation of complex flow features at the wall, taking into account the velocity field and heat transfer. The method is used to investigate several test cases of increasing complexity, including a space vehicle during atmospheric reentry. The tool exhibits interesting efficacy in terms of accuracy versus computational costs required.

A data-constrained sharp Immersed Boundary Method for aerospace applications

TL;DR

This work develops a data-constrained sharp Immersed Boundary Method (IBM) integrated with implicit OpenFOAM solvers to accurately represent wall boundary conditions in aerospace-relevant flows. A Luenberger observer drives a time-dependent source-term framework at ghost cells, enabling Dirichlet/Neumann boundary representations through volume forcing rather than explicit wall values, and ensuring stability across unsteady and compressible regimes. The method is validated on a 2D NACA0012 profile, a 3D supersonic sphere, and a realistic IXV re-entry vehicle, showing robust wall-pressure predictions and favorable accuracy-cost trade-offs, particularly for pressure forces, while viscous/shear predictions require higher grid resolution or gradient-constraining strategies. Limitations include underprediction of wall shear due to non-conservative IBM formulations and absence of detailed near-wall turbulence modeling, which are identified as clear avenues for future enhancements. Overall, the approach offers a portable, efficient, and accurate alternative for preliminary aerospace analyses where high-fidelity wall-resolved simulations are prohibitively expensive.

Abstract

A numerical tool relying on sharp Immersed Boundary Method (IBM) is developed for the analysis of aerospace applications. The method, which is conceived for application using segregated solvers relying on implicit time discretization, uses a Luenberger observer to dynamically update the free coefficients governing the numerical algorithm. This technique improves the accuracy of the method and permits to target the representation of complex flow features at the wall, taking into account the velocity field and heat transfer. The method is used to investigate several test cases of increasing complexity, including a space vehicle during atmospheric reentry. The tool exhibits interesting efficacy in terms of accuracy versus computational costs required.

Paper Structure

This paper contains 16 sections, 10 equations, 11 figures, 5 tables.

Table of Contents

  1. Introduction
  2. Numerical tools
  3. Numerical solvers
  4. Incompressible flow solver: PisoFoam
  5. Compressible flow solver: RhoCentralFoam
  6. Sharp IBM based on a Luenberger observer
  7. Implementation of the source terms and boundary condition used
  8. Validation of the IBM tool
  9. Case setup
  10. Results and discussion
  11. Supersonic flow around a sphere
  12. Results and discussion
  13. Simulation of a Re-entry vehicle
  14. Case setup
  15. Results and discussion
  16. ...and 1 more sections

Figures (11)

  • Figure 1: Scheme of application of the ghost cell method proposed by Peron et al. peron2021immersed.
  • Figure 2: Mesh grid topology used for the simulation of NACA 0012 airfoil. The yellow line represent the immersed boundary
  • Figure 3: Instantaneous velocity magnitude field calculated for the case profile_G3Bis_T4
  • Figure 4: Comparison of the average velocity magnitude field for four simulation of the database. Black lines represent velocity streamlines. Results are shown for the simulations (a) profile_G1_T2, (b) profile_G2_T2, (c) profile_G2_T3 and (d) profile_G3Bis_T4
  • Figure 5: Mean pressure distribution around the profile NACA 0012 obtained via IBM. Results are compared with data from a reference body-fitted simulation.
  • ...and 6 more figures