Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Engineering
Microphone-Based Pressure Diagnostics For Boundary Layer Transition, Spencer Everett Lillywhite
Microphone-Based Pressure Diagnostics For Boundary Layer Transition, Spencer Everett Lillywhite
Master's Theses
An experimental investigation of the use low-cost microphones for unsteady total pressure measurement to detect transition from laminar to turbulent boundary layer flow has been conducted. Two small electret condenser microphones, the Knowles FG-23629 and the FG-23742, were used to measure the pressure fluctuations and considered for possible integration with an autonomous boundary layer measurement system. Procedures to determine the microphones’ maximum sound pressure levels and frequency response using an acoustic source provided by a speaker and a reference microphone. These studies showed that both microphones possess a very flat frequency response and that the max SPL of the FG-23629 …
Hot-Wire Anemometer For The Boundary Layer Data System, William D. Neumeister
Hot-Wire Anemometer For The Boundary Layer Data System, William D. Neumeister
Master's Theses
Hot-wire anemometry has been routinely employed for laboratory measurements of turbulence for decades. This thesis presents a hot-wire anemometer suitable for use with the Boundary Layer Data System (BLDS). BLDS provides a unique platform for in- flight measurements because of its small, self-contained, robust design and flexible architecture. Addition of a hot-wire anemometer would provide BLDS with a sensor that could directly measure flow velocity fluctuations caused by turbulence. Hot-wires are commonly operated in constant-temperature mode for high frequency response, but require a carefully tuned bridge. The constant-voltage anemometer (CVA) uses a simple op-amp circuit to improve frequency response over …
Unsteady Total Pressure Measurement For Laminar-To-Turbulent Transition Detection, Akane Sharon Karasawa
Unsteady Total Pressure Measurement For Laminar-To-Turbulent Transition Detection, Akane Sharon Karasawa
Master's Theses
This thesis presents the use of an unsteady total pressure measurement to detect laminar-to-turbulent transition. A miniature dynamic pressure transducer, Kulite model XCS-062-5D, was utilized to measure the total pressure fluctuations, and was integrated with an autonomous boundary layer measurement device that can withstand flight test conditions. Various sensor-probe configurations of the Kulite pressure transducer were first examined in a wind tunnel with a 0.610 m (2.0 ft) square test section with a maximum operational velocity of 49.2 m/s (110 mph), corresponding dynamic pressure of 1.44 kPa (30 psf). The Kulite sensor was placed on an elliptical nose flat plate …