High Reynolds Number Quiet Mach 6 Nozzle Fabrication and Natural Transition Experiments
Abstract
The program involves the fabrication of the expansion portion of the "quiet" nozzle of the Notre Dame Large Mach 6 Quiet Tunnel, as well as an experiment to be performed in the new tunnel that investigates the role of roughness on blunt cone frustum transition. The facility is designed to accommodate models greater than 2 m.in length that reside completely within the quiet region, and reach x-Reynolds numbers of 40M where flight tests indicate turbulent transition occurs. The test article was designed to exploit the large test section. It consists of a 1.6m long 7deg. half-angle right-circular cone. The cone is deigned with two nose tip sections that allow 7different nose tips of different radii to be installed. The larger nose radii are designed to reach conditions that result in neutral growth of the 2nd mode instability, and ultimately transition length reversal. Continued delays in the operation of the Notre Dame quiet tunnel resulted in performing the experiments in the U.S. Air Force Academy Mach 6 Ludwieg tube. This utilized a repurposed 7deg. cone model whose length was extended to achieve natural transition on the model at higher unit Reynolds numbers. This model has three interchangeable nose tips of different radii, with the largest radius capable of neutral 2nd mode growth at the highest unit Reynolds number. The measurements consisted of off-wall measurements of total pressure and total temperature using specially developed high-bandwidth pressure and temperature sensors. The preliminary results look promising, showing differences in the boundary layer development attributable to the nose radius Reynolds numbers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 04, 2022
- Accession Number
- AD1231097
Entities
People
- Corke Thomas
Organizations
- University of Notre Dame