Onset and Stability of Thermally-Driven Fluid Convection in a Vertical Rock Crack and Their Implication for Hydrothermal Ore-Forming Processes

摘要

Dynamic equations controlling the thermally—driven fluid convection in a single rockcrack are established in the paper.The critical criteria for the onset of convection in sucha configuration are found by linear dynamic analysis of the equations and the stability ofthe convection discussed by nonlinear analysis method.The research demonstrates that thecritical Rayleigh number has a magnitude10~3.While the Rayleigh number R of realore—forming fluids exceeds this value,the convection happens,and as R becomeslarger,the fluid convection pattern develops from nonequilibrium steady states to doub-le—periodically produced limit cycles and eventually to chaos(turbulences).The implica-tion of these dynamic analyses for the ore—forming processes of late—magmatichydrothermal deposits is also discussed in the paper.