Buoyant thermal
= Buoyant thermal
A buoyant thermal is a localized rising volume of fluid whose <mass density> is lower than its surroundings. It can form the head of a <starting plume>. A spherical mixed thermal of radius $R$ has volume $V=4\pi R^3/3$ and <reduced gravity> $g_t=g(\rho_0-\rho_t)/\rho_0$ in the <Boussinesq approximation>.