SUMMARYThis paper describes a preliminary numerical analysis of the e ect of duct velocity proÿle and buoyancyinduced ow generated by the heat source on hydrodynamic removal of contaminants contained in cavities. The process of uid renewal in a cavity is modelled via a numerical solution of the NavierStokes equations coupled with the energy equation for transient ows. The foulant has the same density as the uid in the duct and the duct velocity proÿle is considered to be Poiseuille ow and Couette ow, respectively. The results show that the change in Grashof number and duct ow velocity proÿle causes a dramatic di erence in the observed ow patterns and cleaning e ciency. From a cleaning perspective, the results suggest that Couette ow at higher value of Grashof number becomes more e ective in further purging of contaminated uid from a cavity.