High-Repetition-Rate, Two-Line Kr Tagging Velocimetry for Full Boundary Layer Velocity Profile Measurement in a Single Tunnel Test

NASAnbsp;aero-science ground test facilities, including transonic, supersonic and hypersonic wind tunnels,nbsp;provide critical data and fundamental insight required to understand complex phenomena and support the advancement of computational tools for modeling and simulation.nbsp;In these facilities, high-repetition-rate (10 kHzndash;1 MHz) full boundary layer velocity profile measurement techniques are needed to track the turbulent boundary layer dynamics.nbsp;nbsp;Current state-of-the-art boundary measurement capabilities are really limited because of intrusiveness, model surface damaging with high-peak laser intensity, experimental complexity (e.g., need holes on the model), high measurement uncertainty, and low spatiotemporal resolution.nbsp;This proposalnbsp;offers an integrated package of truly cutting-edge,nbsp;high-repetition-rate (up to 1 MHz rate), single-line or two-line KTV system for full boundary layer velocity profile measurement within a single tunnel test. The proposed KTV technique provides high accuracy with high spatiotemporal resolution and will also avoid any potential model damages ndash; enabling measurement everywhere on the model.nbsp;The concepts and ideas proposed are ranging from proof-of-principles demonstration of novel methodologies using a pulse-burst laser pumped Kr-OPO system for boundary profile measurementnbsp;to applications realistic tunnel conditions. The proposed high-repetition-rate KTV system can be also used for Kr-PLIF imaging, providing flow structure and other flow parameters information for understanding of unsteady and turbulent flows, particularly in boundary layers.