Laminarization effects on the dynamics of a disk levitated by incompressible fluid flow
Abstract
A nonlinear ordinary differential equation of motion for a disk parallel to a flat plat and levitated by incompressible turbulent fluid flow supplied from a central orifice was developed. The transient flow velocity and pressure field for the turbulent flow are found by integrating the time averaged NavierStokes equation with power law velocity and shear stress correlations. The results for the turbulent film are coupled with the study of inertia effects on the dynamics of a disk levitated by incompressible laminar flow to determine the results for a laminarizing flow. The transient pressure field is integrated to use in Newton's second law to determine the O.D.E. for the height of the disk as a function of time when the disk is perturbed from its equilibrium state by a forcing function. The theoretical magnitudes, frequencies, and damping coefficients of oscillation are shown to be within 8% of those measured. The numerical solution differs only slightly from the linearized solution: the latter provides relatively accurate closed form expressions for the frequencies and damping coefficients in terms of the geometry, load, mass flow rate, and the fluid properties.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 March 1984
 Bibcode:
 1984STIN...8419770W
 Keywords:

 Differential Equations;
 Incompressible Flow;
 Laminar Flow;
 Levitation;
 Fluid Flow;
 Incompressible Fluids;
 Supercritical Flow;
 Turbulent Flow;
 Fluid Mechanics and Heat Transfer