Uma breve revisão das correlações para tensão de cisalhamento na parede para escoamentos hipersônicos

• Autor(a) principal: Araújo, Pedro Paulo Batista de
• Data de Publicação: 2022
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/46314
• topic: Skin friction drag; Wall shear stress; CFD; Analytical correlations models; Hypersonic flow

This paper addresses the problem of finding the appropriate correlation model for the estimation of drag force in aerospace vehicles that operate at hypersonic conditions. Here the analysis of the spatial variation of the local wall shear stress along a 6.28° ramp wall in a hypersonic flow is considered. Three cases corresponding to flows with Mach numbers corresponding to 3, 7, and 10 were analyzed. A number of correlations for the friction coefficient as proposed by Sommer and Short, Spalding and Chi, van Driest, White and Christoph, Eckert, and Meador and Smart, were applied to evaluate the wall shear using an analytical approach. The thermodynamic properties of the flow downstream of the shock wave, established at the leading edge of the ramp, were estimated using the oblique shock theory. The analytical results were compared to a reference wall shear data numerically obtained using a Reynolds-Averaged Navier-Stokes (RANS) steady-state simulation performed for the same geometry. The working fluid is air, modeled in this paper as a calorically perfect gas. For the closure of the turbulent Reynolds stresses, the k-kl-ω transition model was used. The results established a quantitative comparison between the wall shear stress curves obtained for each method, numerical and analytical. The results points out that most correlations models have low accuracy for the hypersonic flow, which is reasonable since these models were developed from experimental data extracted from supersonic flows. Despite this limitation, the analytical models which satisfactorily predicted the drag coefficient, under the conditions investigated, were the models proposed by Eckert, the model proposed by Sommer and Short for supersonic flows and the Meador and Smart model for hypersonic flow.