High‐order ghost‐point immersed boundary method for viscous compressible flows based on summation‐by‐parts operators

• Published in: International journal for numerical methods in fluids Vol. 89; no. 7; pp. 256 - 282
• Main Authors: Khalili, M. Ehsan, Larsson, Martin, Müller, Bernhard
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 10.03.2019
• Subjects: Aerodynamics; Boundary conditions; Circular cylinders; Compressible flow; compressible viscous flows; Computational fluid dynamics; Computer simulation; Cylinders; Finite differences; high‐order finite difference method; immersed boundary method; Interfaces; Interpolation; Least squares method; Operators (mathematics); Polynomials; Respiratory tract; Vortex shedding
• ISSN: 0271-2091; 1097-0363
• DOI: 10.1002/fld.4696

Summary A high‐order immersed boundary method is devised for the compressible Navier‐Stokes equations by employing high‐order summation‐by‐parts difference operators. The immersed boundaries are treated as sharp interfaces by enforcing the solid wall boundary conditions via flow variables at ghost points. Two different interpolation schemes are tested to compute values at the ghost points and a hybrid treatment is used. The first method provides the bilinearly interpolated flow variables at the image points of the corresponding ghost points and the second method applies the boundary condition at the immersed boundary by using the weighted least squares method with high‐order polynomials. The approach is verified and validated for compressible flow past a circular cylinder at moderate Reynolds numbers. The tonal sound generated by vortex shedding from a circular cylinder is also investigated. In order to demonstrate the capability of the solver to handle complex geometries in practical cases, flow in a cross‐section of a human upper airway is simulated. A high‐order immersed boundary method is devised for the compressible Navier‐Stokes equations by employing high‐order summation‐by‐parts (SBP) difference operators. Two different interpolation schemes are tested to compute values at the ghost points and a hybrid treatment is used. The first method provides the bilinearly interpolated flow variables at the image points of the corresponding ghost points and the second method applies the boundary condition at the immersed boundary by using the weighted least squares method with high‐order polynomials.