A new flux splitting scheme for the Euler equations II: E-AUSMPWAS for all speeds

2021

Applied Sciences

Currently, aerothermal research into scramjet-propelled vehicles characterized by a wedge-shaped section is relatively sparse. Based on the Mach number, grid strategy, and numerical method, an effective simulation scheme for predicting the aerodynamic heat of a scramjet-propelled vehicle during flight is proposed in this paper. At different Mach numbers, the appropriate grid strategy and numerical method were determined by validation tests. Two-dimensional external flow field models based on wedge sections were established and, unlike in blunt bodies, the tests showed that at the high supersonic stage, the ideal cell Reynolds number should be no larger than 16. At the hypersonic stage, the ideal cell Reynolds number and aspect ratio of wall cells near the shock should be no larger than 40, and the AUSM+ flux type performs better than Roe’s FDS flux type at the above stages. The aerothermal prediction indicates that during a flight time of about 34 s, the temperature change reaches about 1913.35 °C, and the maximum average temperature change rate reaches 115 °C/s.

Section: Simulation Parametersmentioning

confidence: 99%

“…Ref. [13] reveals that the aspect ratio of wall cells near the shock is a major factor and Ref. [14] suggests that the aspect ratio of wall cells near the shock should be larger than six for predicting hypersonic heating, taking a blunt body and a blunt cone as examples.…”

Section: Introductionmentioning

confidence: 99%

An Effective Simulation Scheme for Predicting the Aerodynamic Heat of a Scramjet-Propelled Vehicle

2021

Applied Sciences

“…Numerical experiments [9,8,18] demonstrate that these all-speed schemes have good performance in hypersonic heating computations. Similar improved all-speed flux splitting flux functions based on AUSM-family schemes are also developed by Qu et al [19,20,21]. Their proposed AUSM-type schemes have also shown great potential in computing hypersonic heating problems.…”

Section: Introductionmentioning

confidence: 87%

“…where F hllem/hllc represent the original numerical fluxes defined in (17) and (20), and F p denotes the modified flux function,…”

Section: Shock Stabilization By Pressure Dissipative Fluxmentioning

confidence: 99%

A unified construction of all-speed HLL-type schemes for hypersonic heating computations

Xie¹,

Tian²,

Zhang³

et al. 2021

Preprint

In this paper, a unified framework to develop all-speed HLL-type schemes for hypersonic heating computations is constructed. Such a unified construction method combines two effective improving techniques: a shock robustness improvement and a low-Mach number fix. It is implemented by properly modifying the approximate solutions of the local Riemann problem in the HLL framework, resulting in two all-speed HLL-type schemes, namely ASHLLC and ASHLLEM solvers. Results from both numerical analysis and experiments demonstrate that the newly proposed schemes not only preserve desirable properties of their original versions, but are also able to provide accurate and robust solutions for complex flows ranging from low-Mach number incompressible to hypersonic compressible regimes. Thus, both the ASHLLC and ASHLLEM schemes can be used as reliable methods for hypersonic heating computations.

“…Node-to-midpoint interpolation is performed on characteristic fields to alleviate spurious oscillations Deng and Zhang (2000). While solving the Euler equations, a robust and highresolution numerical flux scheme is also an essential component of the numerical solver Zhang et al (2016Zhang et al ( , 2017; Qu et al (2018). For high-order methods the numerical flux schemes can be influential for the overall robustness and resolution Drikakis and Tsangaris (1993); Wang et al (2016).…”

Section: Inviscid Burgers' Equationmentioning

confidence: 99%

A multi-resolution weighted compact nonlinear scheme for hyperbolic conservation laws

Wang

International Journal of Computational Fluid Dynamics

2020

A typical weighted compact nonlinear scheme (WCNS) uses a convex combination of several low-order polynomials approximated over selected candidate stencils of same width, achieving non-oscillatory interpolation near discontinuities and high order accuracy for smooth solutions. In this paper, we present a new multi-resolution fifth-order WCNS by making use of the information of polynomials on three nested central spatial sub-stencils having first-, third-and fifth-order accuracy, respectively. The new scheme is capable of obtaining high-order spatial interpolation in smooth regions, and it is characterized by the feature of gradually degrading from fifth-order down to first-order accuracy as large stencils deemed to be crossing strong discontinuities. The advantages of the present scheme include the superior resolution for highwavenumber fluctuations and the flexibility of implementing different numerical flux functions.