Efficient implementation of high-order WENO schemes with sharing function for solving Euler equations

Due to the high-order accuracy and essentially non-oscillatory (ENO) property, the weighted ENO (WENO) schemes have a wide range of successful applications. The component-wise reconstruction WENO (CP WENO) scheme for fluxes or variables has simple formulations but it may produce numerical oscillations near discontinuities when solving the Euler equations. Although the characteristic-wise reconstruction WENO (CH WENO) scheme can reduce such oscillations, it involves too many characteristic projection operations. In this paper, first, we introduced a sharing function to indicate the discontinuities in the Euler equations and then constructed new adaptive characteristic-wise WENO (Ada-WENO) scheme and common-weights WENO (Co-WENO) scheme with this function. Several one and two dimensional problems are used to test the performances of Ada-WENO and Co-WENO. Numerical results show that, Ada-WENO can reduce the computational cost of CH WENO while maintaining its oscillation-free property since it only switches from CP WENO to CH WENO near discontinuities, and Co-WENO can reduce the cost and oscillations of CP WENO, but it may still generate few oscillations.