Observation of unsteady motion induced by counterflow jet on blunt body in hypersonic flow

This study focuses on the drag reduction phenomenon caused by counterflow. Experimental studies were performed using a hypersonic shock tunnel to observe the effect of drag reduction caused by unstable counterflow. In the long penetration mode, a considerably asymmetric shock wave structure was obse...

Full description

Saved in:
Bibliographic Details
Published in:Journal of visualization 2022-02, Vol.25 (1), p.1-14
Main Authors: Kim, Duk-Min, Kim, Yongchan, Roh, Tae-Seong, Lee, Hyoung Jin
Format: Article
Language:English
Subjects:
Asymmetry
Blunt bodies
Classical and Continuum Physics
Computer Imaging
Counterflow
Drag reduction
Engineering
Engineering Fluid Dynamics
Engineering Thermodynamics
Heat and Mass Transfer
Hypersonic flow
Hypersonic shock
Pattern Recognition and Graphics
Penetration
Pressure
Regular Paper
Shock tunnels
Vertical oscillations
Vision
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study focuses on the drag reduction phenomenon caused by counterflow. Experimental studies were performed using a hypersonic shock tunnel to observe the effect of drag reduction caused by unstable counterflow. In the long penetration mode, a considerably asymmetric shock wave structure was observed. Horizontal and vertical oscillations occurred, resulting in asymmetric changes in the recirculation region when the injection pressure was low. Based on the experimental results, it was confirmed that the surface pressure decreased near recirculation regions, contributing to the drag reduction. In contrast, the occurrence of reattachment shock could result in a large increase in surface pressure. These results suggest that the drag reduction effect depends on not only the penetration length but also the flow structure. At a specific injection pressure, the Long Penetration Mode (LPM) and Short Penetration Mode (SPM) alternated; however, when the injection pressure was sufficiently high, only the SPM occurred, and a transition to a completely stable flow occurred. A maximum drag reduction of approximately 53% was observed in this hypersonic flow experiment. Graphic abstract
ISSN:1343-8875
1875-8975
DOI:10.1007/s12650-021-00773-z