An improved fractional-step method on co-located unstructured meshes for weakly compressible flow simulations. (15th March 2023)

• Record Type: Journal Article
• Authors: Cang, Yu; Wang, Lipo
• Is Part Of: Computers & fluids. Volume 253(2023)
• Publication Date: 2023-03-15
• Subjects: 76M12 -- 76N06; Co-located arrangement -- Projection method -- Low Mach number variable-density flow -- Helmholtz equation -- Pressure correction; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2022.105775
• Languages: English
• ISSNs: 0045-7930

Abstract

Abstract: A pressure-based semi-implicit algorithm on the cell-centered unstructured mesh with co-located variable arrangement has been developed to efficiently and robustly calculate the low-Mach number variable-density flows, where thermal dilatation is important. The proposed fractional-step method follows the conventional operator-splitting procedure, but is incorporated with several improvements. Instead of the traditional Poisson equation, the Helmholtz equation is formulated for the pressure correction. The finite-volume method with second-order accuracy in space is used to discretize the governing equations. Numerical tests justify the effectiveness and robustness of this improved algorithm. Highlights: Semi-implicit algorithm for both weakly compressible and nearly incompressible flow. Pressure disturbance propagates at finite rate via the Helmholtz equation. Non-physical oscillations are systematically suppressed under cell-centered FVM.