Studies on gravitational spreading currents

• Main Author: Chen, Jing-Chang
• Format: Others
• Published: 1980
• Online Access: https://thesis.library.caltech.edu/6077/1/Chen_jc_1980.pdf; Chen, Jing-Chang (1980) Studies on gravitational spreading currents. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/16RG-AZ72. https://resolver.caltech.edu/CaltechTHESIS:09302010-090407312 <https://resolver.caltech.edu/CaltechTHESIS:09302010-090407312>

<p>The objective of this investigation is to examine the buoyancy-driven gravitational spreading currents, especially as applied to ocean disposal of wastewater and the accidental release of hazardous fluids.</p> <p>A series of asymptotic solutions are used to describe the displacement of a gravitationally driven spreading front during an inertial phase of motion and the subsequent viscous phase. Solutions are derived by a force scale analysis and a self-similar technique for flows in stagnant, homogeneous, or linearly density-stratified environments. The self-similar solutions for inertial-buoyancy currents are found using an analogy to the well-known shallow-water wave propagation equations and also to those applicable to a blast wave in gasdynamics. For the viscous-buoyancy currents the analogy is to the viscous long wave approximation to a nonlinear diffusive wave, or thermal wave propagation. Other similarity solutions describing the initial stage of motion of the flow formed by the collapse of a finite volume fluid are developed by analogy to the expansion of a gas cloud into a vacuum. For the case of a continuous discharge there is initially a starting jet flow followed by the buoyancy-driven spreading flow. The jet mixing zone in such flows is described using Prandtl's mixing length theory. Dimensional analysis is used to derive the relevant scaling factors describing these flows.</p>