On the design of quiet hypersonic wind tunnels

This document presents a thorough literature review on the development of hypersonic quiet tunnels. The concept of boundary layer transition in high-speed flows is presented first. Its consequences on the free-stream turbulence levels in ground facilities are reviewed next, demonstrating that running boundary layers along the nozzle walls must remain laminar for quiet operation. The design key points that enable laminar boundary layers and hypersonic operation with low free-stream noise levels are then identified and discussed. The few quiet facilities currently operating through the world are also presented, along with their design characteristics and performances. The expected characteristics and performances of a European quiet tunnel are also discussed, along with flow characterization methodologies and different measurement techniques. It is finally shown that the required expertise to establish the first European quiet hypersonic wind tunnel is mostly at hand.