Author
Okazaki Takuro
Bio: Okazaki Takuro is an academic researcher from University of Tokyo. The author has contributed to research in topics: Rayleigh number & Grashof number. The author has an hindex of 1, co-authored 1 publications receiving 89 citations.
Papers
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TL;DR: In this article, heat transfer from a horizontal fine cylinder by pure forced convection at small Reynolds numbers or by pure free convection in small Grashof numbers is analyzed without restriction on Prandtl number by the method of joining the circumferential average temperature in the concentric layer around the cylinder governed mainly by conduction to that in the wake or plume governed mainly with convection.
92 citations
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TL;DR: In this article, a single comprehensive equation is developed for the rate of heat and mass transfer from a circular cylinder in crossflow, covering a complete range of Pr (or Sc) and the entire range of Re for which data are available.
Abstract: A single comprehensive equation is developed for the rate of heat and mass transfer from a circular cylinder in crossflow, covering a complete range of Pr (or Sc) and the entire range of Re for which data are available. This expression is a lower bound (except possibly for RePr < 0.2); free-stream turbulence, end effects, channel blockage, free convection, etc., may increase the rate. In the complete absence of free convection, the theoretical expression of Nakai and Okazaki may be more accurate for RePr < 0.2. The correlating equation is based on theoretical results for the effect of Pr in the laminar boundary layer, and on both theoretical and experimental results for the effect of Re. The process of correlation reveals the need for theoretical results for the effect of Pr in the region of the wake. Additional experimental data for the effect of Pr at small Pe and for the effect of Re during the transition in the point of separation are also needed.
849 citations
TL;DR: In this paper, the Navier-Stokes and energy equations were solved using an elliptic numerical procedure for a horizontal isothermal cylinder, and the flow approach natural convection from a line heat source as Ra → 0 and laminar boundary-layer flow as Ra→ ∞.
308 citations
TL;DR: In this article, the laminar combined convection heat transfer from an isothermal horizontal circular cylinder is studied for the two cases when the forced flow is directed either vertically upward (parallel flow) or vertically downward (contra flow).
134 citations
TL;DR: In this paper, the problem of laminar mixed convection from a horizontal isothermal cylinder is considered and the free stream direction is assumed to be horizontal and perpendicular to the cylinder axis.
104 citations
TL;DR: The theoretical results show that the dominant contribution to the laser frequency shift comes from adiabatic temperature shifts in the surrounding air at lower frequencies and from pressure at higher frequencies.
Abstract: Contributions to the acoustic signal sensitivity of fiber distributed-feedback (DFB) lasers in air are investigated both theoretically and experimentally The theoretical results show that the dominant contribution to the laser frequency shift comes from adiabatic temperature shifts in the surrounding air at lower frequencies and from pressure at higher frequencies The transition frequency was found to be between 5 and 20 kHz, depending on the elastic boundary conditions of the fiber laser The acoustically induced frequency shifts of two fiber DFB lasers were measured, and the sensitivities varied from 061 MHz/Pa at a 100-Hz acoustic frequency to 034 kHz/Pa at a 15-kHz acoustic frequency
73 citations