압축성유동에서 ACM방법을 이용한 3차지차수를 갖는 비진동 수치해법연구

Abstract

In this research, uniformly third-order schemes are used to capture shocks and contact surfaces in unsteady compressible flows. In order to obtain high resolutions near the discontinuities and to resolve the small amplitudes, an ACM(artificial compression method) technique is successfully employed to the third-order UNO(uniformly nonoscillatory) scheme. The UNO schemes are improved here so as to produce symmetric properties in the propagating waves. To reduce the additional computational time for the ACM, the original forms of ACM are modified to a delta form and are applied to all the characteristic waves, including the acoustic wave. The UNO schemes are tested for various numerical CFL numbers in scalar waves and tested, wellknown one-dimensional problems. These schemes are extended to one-dimensional and two-dimensional Euler equations to calculate the shock, contact surface and expansion waves. Results are compared to show differences among the third order UNO schemes with and without ACM.