Asymmmetry and unsteadiness of incipient separation of nominally axisymmetric turbulent boundary layer

Shigeaki Masuda, Kouhel Okada, Rei Takagi, Shinnosuke Obi

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

Abstract

Unsteady and asymmetric behavior of separation of nominally axisymmetric and steady turbulent boundary layer in an axisymmetric expansion is investigated. The test diffusers have the total divergence angle from 8 to 50deg and length-to-diameter ratio of 8. Bulk Reynolds number is ranging between 2.5 × 104and 2.4 × 105. The wall static pressure fluctuation increases monotonically with increasing divergence angle up to 25° and then decreases. The wall static pressure exhibits large scale law frequency fluctuations, occurring almost concurrently in the entire passage. Distributions of both mean velocity and reverse flow fraction in a cross-stream plane show axial-asymmetry of the separated flow, suggesting the rapid growth of circumferential non-uniformity upstream. The velocity measurements employing a split film probe to distinguish the flow directions exhibits intermittent flow reversal with higher velocity as compared with forward flow. The conditional average of wall hot film signals reveals the steep decrease at the incipience of flow reversal.

Original languageEnglish
Title of host publicationProceedings of the 4th ASME/JSME Joint Fluids Engineering Conference
Subtitle of host publicationVolume 2, Part B, Symposia
EditorsA. Ogut, Y. Tsuji, M. Kawahashi, A. Ogut, Y. Tsuji, M. Kawahashi
Pages1103-1108
Number of pages6
Publication statusPublished - 2003 Dec 1
Event4th ASME/JSME Joint Fluids Engineering Conference - Honolulu, HI, United States
Duration: 2003 Jul 62003 Jul 10

Publication series

NameProceedings of the ASME/JSME Joint Fluids Engineering Conference
Volume2 B

Other

Other4th ASME/JSME Joint Fluids Engineering Conference
CountryUnited States
CityHonolulu, HI
Period03/7/603/7/10

ASJC Scopus subject areas

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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  • Cite this

    Masuda, S., Okada, K., Takagi, R., & Obi, S. (2003). Asymmmetry and unsteadiness of incipient separation of nominally axisymmetric turbulent boundary layer. In A. Ogut, Y. Tsuji, M. Kawahashi, A. Ogut, Y. Tsuji, & M. Kawahashi (Eds.), Proceedings of the 4th ASME/JSME Joint Fluids Engineering Conference: Volume 2, Part B, Symposia (pp. 1103-1108). (Proceedings of the ASME/JSME Joint Fluids Engineering Conference; Vol. 2 B).