A 3-POINT COMBINED COMPACT DIFFERENCE SCHEME

A new three-point combined compact difference (CCD) scheme is develope d for numerical models, The major features of the CCD scheme are: thre e paint, implicit. sixth-order accuracy, and inclusion of boundary val ues. Due to its combination of the first and second derivatives, the C CD scheme becomes more compact and more accurate than normal compact d ifference schemes. The efficient twin-tridiagonal (for calculating der ivatives) and triple-tridiagonal (for solving partial difference equat ion with the CCD scheme) methods are also presented. Besides, the CCD scheme has sixth-order accuracy at periodic boundaries and fifth-order accuracy at nonperiodic boundaries, The possibility of extending to a three-point eighth-order scheme is also included. (C) 1998 Academic P ress.