Schlieren visualization of transonic and supersonic flow over a sphere at reynolds number between 103and 105through free-flight tests

Takayuki Nagata, Akito Noguchi, Taku Nonomura, Toshihiro Ogawa, Kiyonobu Ohtani, Kesuke Asai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In this study, free-flight tests of a sphere at a Reynolds number between 5.7 × 103and 3.1 × 105under transonic to supersonic condition is conducted using ballistic range and investigate the flow over a sphere under compressible low-Reynolds number conditions. The flow visualization is carried out by schlieren technique. A free-flight Reynolds number is between 5.7 × 103and 3.1 × 105and a free-flight Mach number is between 0.9 and 1.6. To realize the compressible low-Reynolds number flow, the flow visualization is carried out under low-pressure conditions with a small sphere (minimum diameter is 2.0 mm). in addition, the time-averaged images around a sphere are obtained and compared with previous numerical results for the Reynolds number between 50 and 1000. From the experimental results, the near field and far field flow structure at the Reynolds number of between 5.7 × 103and 3.1 × 105under supersonic conditions are visualized. As a result, following characteristics are clarified: 1) the perturbation amplitude of wake vortex is attenuated as a free-flight Mach number increases, 2) mode of wake structure is changed by changing the free-flight Mach number, 3) there is no Reynolds number dependences on the separation point, but a length of the recirculation region is influenced by the Reynolds number.

Original languageEnglish
Title of host publicationAIAA Scitech 2019 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105784
DOIs
Publication statusPublished - 2019 Jan 1
EventAIAA Scitech Forum, 2019 - San Diego, United States
Duration: 2019 Jan 72019 Jan 11

Publication series

NameAIAA Scitech 2019 Forum

Conference

ConferenceAIAA Scitech Forum, 2019
CountryUnited States
CitySan Diego
Period19/1/719/1/11

ASJC Scopus subject areas

  • Aerospace Engineering

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