Time and Spatially Resolved Interaction Between Surface and Freestream Nuclei with the Surrounding Flow During Cavitation Inception
Abstract
While there is ample data indicating that cavitation inception is dependent on the concentrationand nature of cavitation nuclei, very little experimental data exits on how these nuclei interact withhigh Reynolds number turbulent flows as they grow from microscopic to visible scales. The dearthof information is caused by the challenge in resolving explosive processes, which occur inmicroseconds, and involve at least six orders of magnitude change in the bubble size. Takingadvantage of recent advances in high speed imaging, this proposal requests funding for assemblinga 5 MHz high speed digital holographic microscopy (DHM) system aimed at quantifying the flownucleiinteractions as visible cavitation develops from surface and freestream micro-nuclei.Specifically, our objectives are: (i) To measure the growth of freestream and/or surface cavitationnuclei from microscopic to macroscopic scales, fully resolving the shape of the nucleus during thisprocess. (ii) To measure the velocity and pressure distributions in the flow surrounding a growing(and collapsing) cavitation bubble as it interacts with, and presumably modifies, high Reynoldsnumber turbulent boundary layers. Such data is essential for quantifying the interaction of nucleiwith the surrounding flow. (iii) To measure the flow and pressure distributions around cavitationevents occurring in a turbulent shear flow, where bubbles interact with vortices. (iv) To resolvethe attachment of a cavitation nucleus growing in a boundary layer to the wall as it clears the thinliquid layer separating it from the surface. (v) To characterize the effect of surface properties onthe development of cavitation from surface nuclei in high Reynolds number flows. (vi) Tovisualize the evolution of compression (shock) and expansion waves generated during cavitation,and evaluate their impact on the local flow.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812331
Entities
People
- Joseph Katz
Organizations
- Johns Hopkins University
- Office of Naval Research
- United States Navy