此流体模拟基于paperbyStam.在第7页，他描述了平流背后的基本思想:Startwithtwogrids:onethatcontainsthedensityvaluesfromtheprevioustimestepandonethatwillcontainthenewvalues.Foreachgridcellofthelatterwetracethecell’scenterpositionbackwardsthroughthevelocityfield.Wethenlinearlyinterpolatefromthegridofpreviousdensityvaluesanda