Laval Nozzles: Design, Characterization, and Applications
Résumé
This chapter focuses on Laval nozzles. After emphasizing their ubiquitous usage in a large variety of scientific fields, a methodology, based on the method of characteristics and Michel’s integrals, is presented in detail to calculate their divergent contours taking into account the boundary layer. The main experimental techniques allowing the characterization of the flow exiting the nozzle are then reviewed. These include the Pitot tube, rotational spectroscopy, and velocimetry. Many examples of the temperature evolution downstream of Laval nozzles issued from various laboratories are depicted to illustrate the high level of uniformity that a supersonic flow expanding through these ducts can achieve. The versatility of Laval nozzles is also highlighted in detail, making them real temperature tunable tools. The chapter ends with a historical review of the development of the CRESU technique worldwide with special attention to the recent improvements for the generation of pulsed uniform supersonic flows. © 2022 by World Scientific Publishing Europe Ltd.