A System to Measure Turbulent Lengthscales on Submerged Bodies of Revolution
Abstract
A system has been developed to measure the turbulent lengthscales in the flow about a submerged body of revolution. The system consists of two Laser Doppler Velocimetry (LDV) probes mounted inside the body of revolution with the beams projected outside of the body through conformal windows. The measurement volumes of the two probes can be independently positioned within a plane perpendicular to the body axis. The probes are used to measure velocity time series at various spacings in the flow field. Auto- and cross-correlations are computed for each measurement pair, from which integral lengthscales are then found. Measurements are compared to canonical data from a turbulent free shear jet. In this paper, the system is described and its theory of operation detailed. Methods of computing the velocity correlations from the random-arrival-time LDV measurements are presented, and a new noise-removal scheme for non-uniformly sampled data is introduced. Six methods for calculating the integral lengthscale from autocorrelation data are reviewed, and the results discussed for the present jet data measured with LDV.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 04, 2017
- Source ID
- 10.5957/attc-2017-0041
Entities
People
- Christopher J. Chesnakas
- Daniel R. Cadel
Organizations
- Naval Surface Warfare Center