Abstract
The rise of the unsteady pressure magnitude along the surface of a cascade blade in unsteady transonic flow is examined. It is shown that a similar rise in the unsteady pressure may occur for high subsonic flows where the mean flow is near sonic condition. For a subsonic cascade this unsteady pressure bulge is found to be associated with the cut-on of a new acoustic mode in the upstream direction. The level of the pressure bulge is significantly reduced as a downstream propagating mode cuts on. It is therefore proposed that this phenomenon is the result of the blockage of upstream propagating acoustic waves by the transonic mean flow. A transonic convergent-divergent nozzle is used as a model for investigating the acoustic blockage effect. Analytical and numerical computations using unsteady nonlinear Euler equations are then carried out to analyze and quantify the upstream and dowstream propagation of acoustic disturbances in the nozzle. The results confirm the sharp rise in the pressure of the upstream propagating disturbances at the nozzle throat as a result of the acoustic blockage.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
