On some efecitve bott-type advective schemes

摘要

One of the key problems in airborn pollution modellign is the accuracy and the speed of the hnumericla schemes.THe description of the advection porcesses is still a real schallenge for dispersion meodellers.A lot of mehtods and schemes have been proposed in the literature but only a few of them are suitable and of practicla use.One of the most widely used schemes is that elaborated by Bott (1989).In the bott xheme,the advective fluxes at the edges of each grid cell are computed utilising hte integrate flux ocncpt.THey are normalised adn then limited by upper and lower values.The scheme porduced is cnservative and positively definite with small numericla diffusion and good transport abilituy.These properties make the Bott scheme very attractive for further impoverments and optimisations.In this stuyd,comparative tests of the Bott(1989) scheme and some newy created schemes are porvided.