A meshless method for compressible flows with the HLLC Riemann solver

TL;DR

This paper develops a meshless HLLC Riemann solver for compressible flows, capable of handling both gases and liquids using a least-squares approach and the stiffened gas equation of state, validated through diverse simulations.

Contribution

It introduces a comprehensive meshless HLLC solver framework for compressible flows, including liquids, with detailed implementation and validation.

Findings

Accurately simulates shock tube problems for gases and liquids.

Effectively models supersonic and transonic flows over aerofoils.

Matches well with experimental and exact solutions.

Abstract

The HLLC Riemann solver, which resolves both the shock waves and contact discontinuities, is popular to the computational fluid dynamics community studying compressible flow problems with mesh methods. Although it was reported to be used in meshless methods, the crucial information and procedure to realise this scheme within the framework of meshless methods were not clarified fully. Moreover, the capability of the meshless HLLC solver to deal with compressible liquid flows is not completely clear yet as very few related studies have been reported. Therefore, a comprehensive investigation of a dimensional non-split HLLC Riemann solver for the least-square meshless method is carried out in this study. The stiffened gas equation of state is adopted to capacitate the proposed method to deal with single-phase gases and/or liquids effectively, whilst direct applying the perfect gas equation of state for compressible liquid flows might encounter great difficulties in correlating the state variables. The spatial derivatives of the Euler equations are computed by a least-square approximation and the flux terms are calculated by the HLLC scheme in a dimensional non-split pattern. Simulations of gas and liquid shock tubes, moving shock passing a cylinder, internal supersonic flows in channels and external transonic flows over aerofoils are accomplished. The current approach is verified by extensive comparisons of the produced numerical outcomes with various available data such as the exact solutions, finite volume mesh method results, experimental measurements or other reference results.