LAUSR

Summary Hybrid schemes are very efficient for complex compressible flow simulation. However, for most existing hybrid schemes in literature, empirical problem-dependent parameters are always needed to detect shock waves and hence greatly decrease the robustness and accuracy of the hybrid scheme. In this paper, based on the nonlinear weights of the weighted essentially non-oscillatory (WENO) scheme, a novel weighting switch function is proposed. This function approaches 1 with high-order accuracy in smooth regions and 0 near discontinuities. Then, with the new weighting switch function, a seventh-order hybrid compact-reconstruction WENO scheme (HCCS) is developed. The new hybrid scheme uses the same stencil as the fifth-order WENO scheme, and it has seventh-order accuracy in smooth regions even at critical points. Numerical tests are presented to demonstrate the accuracy and robustness of both the switch function and HCCS. Comparisons also reveal that HCCS has lower dissipation and less computational cost than the seventh-order WENO scheme. Copyright © 2016 John Wiley & Sons, Ltd.