Affordable, entropy-consistent Euler flux functions II: Entropy production at shocks

• Published in: Journal of computational physics Vol. 228; no. 15; pp. 5410 - 5436
• Main Authors: Ismail, Farzad, Roe, Philip L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Inc 20.08.2009; Elsevier
• Subjects: Computational techniques; Entropy conservation; Entropy consistency; Entropy production; Entropy-stability; Exact sciences and technology; Mathematical methods in physics; Physics; Shock stability; Entropy conservation; Entropy-stability; Entropy production; Entropy consistency; Shock stability; Discontinuity; Second order; Third order; Consistency; Entropy; Calculation methods; Instability; Calculation
• ISSN: 0021-9991; 1090-2716
• DOI: 10.1016/j.jcp.2009.04.021

In this paper, an entropy-consistent flux is developed, continuing from the work of the previous paper. To achieve entropy consistency, a second and third-order differential terms are added to the entropy-conservative flux. This new flux function is tested on several one dimensional problems and compared with the original Roe flux. The new flux function exactly preserves the stationary contact discontinuity and does not capture the unphysical rarefaction shock. For steady shock problems, the new flux predicts a slightly more diffused profile whereas for unsteady cases, the captured shock is very similar to those produced by the Roe- flux. The shock stability is also studied in one dimension. Unlike the original Roe flux, the new flux is completely stable which will provide as a candidate to combat multidimensional shock instability, particularly the carbuncle phenomenon.