Abstract
Flow parameters introduced in the authors' previous model on the head of the gravity currents which govern the variations of flow depth, density and velocity of the head of the currents have been examined for the inclined plume and thermal. These parameters are entrainment coefficient, E, and expansion coefficient, m, which indicates the growth rate of flow depth due to the sum of entrainment and streamwise convergence of the depth averaged velocity. As the results of examination, the values of m showed no significant difference between these flows when bottom slope and width enlarging rate are set at almost the same values for both flows. The value of E, however, showed significant difference between these flows. The E/m value of a thermal is greater than unity, while that of plume is a little smaller than unity. This expresses the fundamental difference between these two types of flow. The above mentioned model explains well the difference between the properties of both density and velocity variations of the heads of plume and thermal.
