Reproduction of the unsteady pressure field of Karman vortex street behind a square cylinder by hybrid wind tunnel

Takayuki Yamagata, Hikaru Shibata, Toshiyuki Hayase, Kasper Smit

Research output: Contribution to journalArticlepeer-review


This paper deals with the hybrid wind tunnel which combines wind tunnel experiment and numerical simulation to obtain the exact and detailed information of real flows. The hybrid wind tunnel, which is based on the observer theory, utilizes partial pressure measurement of a real flow for the numerical simulation. The measured pressure is included by the simulation through a feedback loop to overcome the difficulty of specifying exact boundary or initial conditions as well as the effect of modeling error. In this paper, the reproducibility of a pressure field on the hybrid wind tunnel, which treats a fundamental flow with the Karman vortex street behind a square cylinder, is investigated by comparison with pressure measurement on the side wall of the wind tunnel. As compared with ordinary simulation, mean pressure and pressure fluctuation reproduced by the hybrid wind tunnel agree well with that of experiment with large time steps which are inappropriate for ordinary simulations. Especially, the oscillation of the pressure synchronizes with that of experiment at -4D ≲x≲3D (D: cylinder width) on the side wall of the wind tunnel, showing positive correlation with the experiment. The reduction of computational cost by using large time steps enables the hybrid wind tunnel to perform real time analysis of real flows.

Original languageEnglish
Pages (from-to)362-369
Number of pages8
JournalNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Issue number2
Publication statusPublished - 2008 Feb


  • Flow measurements
  • Flow observer
  • Hybrid wind tunnel
  • Karman vortex
  • Measurement-integrated simulation
  • Numerical simulation
  • Pressure distribution
  • Real time analysis
  • Unsteady flow
  • Vortex


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