Unsteady forces on a body immersed in viscous fluids. (2nd report, Uniformly accelerated flat plate, elliptic and circular cylinders)

1984 ◽  
Vol 50 (460) ◽  
pp. 3142-3151
Author(s):  
Takahiko TANAHASHI ◽  
Tatsuo SAWADA ◽  
Eriya KANAI ◽  
Akira CHINO ◽  
Tsuneyo ANDO
Keyword(s):  
Flat Plate ◽  
Viscous Fluids ◽  
Circular Cylinders ◽  
Unsteady Forces

scholarly journals Unsteady Forces Acting on a Body Immersed in Viscous fluids : 2nd Report, Uniformly Accelerated Flat Plate, Elliptic Cylinder and Circular Cylinder

1985 ◽  
Vol 28 (242) ◽  
pp. 1634-1641
Author(s):  
Takahiko TANAHASHI ◽  
Tatsuo SAWADA ◽  
Eriya KANAI ◽  
Akira CHINO ◽  
Tsuneyo ANDO
Keyword(s):  
Circular Cylinder ◽  
Flat Plate ◽  
Elliptic Cylinder ◽  
Viscous Fluids ◽  
Unsteady Forces

scholarly journals Unsteady Boundary Layers on a Flat Plate Disturbed by Periodic Wakes: Part I — Measurement of Wake-Affected Heat Transfer and Wake-Induced Transition Model

1994 ◽  
Author(s):  
K. Funazaki
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Rotating Disk ◽  
Circular Cylinders ◽  
Transition Model ◽  
Time Diagram ◽  
Test Conditions ◽  
Intermittency Factor ◽  
Unsteady Boundary Layers ◽  
Good Agreement

Measurements of wake-affected heat transfer distributions on a flat plate are made by use of a wake generator that consists of a rotating disk and several types of circular cylinders. The main purpose of this study is to construct a wake-induced transition model in terms of an intermittency factor, considering the evolution of the wake-induced turbulent region, a so-called turbulent patch in a distance-time diagram. A comparison between the proposed transition model and the measured heat transfer data reveals that the transition model yields good agreement with the measured data of all test conditions in this study.

Study of Possibility of Simulation of Thick Turbulent Boundary Layer on a Flat Plate of Limited Length

2012 ◽  
Vol 7 (3) ◽  
pp. 44-56
Author(s):  
Vladimir Kornilov
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Flat Plate ◽  
Effective Means ◽  
Leading Edge ◽  
Circular Cylinders ◽  
Mean Velocity ◽  
Velocity Scale ◽  
Limited Length ◽  
Fluctuation Boundary

The experiments directed to the study of possibility of simulation of thick equilibrium (according to Clauser) incompressible turbulent boundary layer on a flat plate of limited length have been performed. It is shown that the artificial generators manufactured from circular cylinders (pins) of adjustable height h, which were mounted normal to the wall in a staggered order in two rows in х in vicinity of the plate leading edge are quite effective means of artificial boundary layer thickening. In most cases both the averaged and fluctuation boundary-layer characteristics at a downstream distance about 530 cylinder diameters have values typical for naturally-developed turbulent boundary layer. Mean velocity profiles in the artificially thickened boundary layer taken in wall-law variables are approximated with a good accuracy by the wellknown velocity law valid for canonic boundary layer and they are generalized by a unified dependence using empirical velocity scale

Stability Analysis to Predict Vortex Street Characteristics and Forces on Circular Cylinders

1987 ◽  
Vol 109 (2) ◽  
pp. 148-154 ◽  
Author(s):  
G. Triantafyllou ◽  
M. Triantafyllou ◽  
C. Chryssostomidis
Keyword(s):  
Stability Analysis ◽  
Closed Form ◽  
Critical Point ◽  
Strouhal Number ◽  
Vortex Street ◽  
Circular Cylinders ◽  
Absolute Instability ◽  
Instability Analysis ◽  
Unsteady Forces ◽  
Good Agreement

The characteristics of the wake are predicted accurately by the critical point of the absolute instability supported by the wake profiles immediately behind the cylinder. Measured profiles at Rn = 56 provide Strouhal number St = 0.13 and at Rn = 140,000 St = 0.21 both in good agreement with experiment. It is also shown that at the undercritical Rn = 34 or for a symmetric array of vortices the instability is of the convective type, decaying behind the cylinder once the excitation is removed. Finally, it is shown that a model of the wake, based on the results of the instability analysis, is sufficient to obtain good estimates of the steady and unsteady forces on the cylinder. Closed-form expressions for the forces are obtained within this approximation.

scholarly journals Cocurrent flows of two immiscible viscous fluids over a flat plate

AIChE Journal ◽  
1967 ◽  
Vol 13 (2) ◽  
pp. 396-397
Author(s):  
Hsu-Chieh Yeh ◽  
Wen-Jei Yang
Keyword(s):  
Flat Plate ◽  
Viscous Fluids

Local Force Measurements on Finite-Span Cylinders in a Cross-Flow

1987 ◽  
Vol 109 (2) ◽  
pp. 136-143 ◽  
Author(s):  
V. K. Sin ◽  
Ronald M. C. So
Keyword(s):  
Free Stream ◽  
Cross Flow ◽  
Circular Cylinders ◽  
Two Dimensional ◽  
Force Measurements ◽  
Unsteady Forces ◽  
Free Stream Turbulence ◽  
Finite Span ◽  
Present Technique ◽  
Unsteady Force

A technique employing a three-axis piezoelectric load cell is developed to measure local unsteady forces induced on cylinders placed in a cross flow. Verification of the technique is carried out with a two-dimensional circular cylinder. All measurements are made at a Reynolds number of ∼4.8 × 104 and a free-stream turbulence of ∼1.5 percent. The local two-dimensional unsteady lift measurement is found to be in excellent agreement with spanwise-averaged data reported in the literature, thereby validating the feasibility of the present technique. Steady and unsteady force measurements on finite-span circular cylinders are reported and compared with available data in the literature.

Simulations of the viscous flow normal to an impulsively started and uniformly accelerated flat plate

1996 ◽  
Vol 328 ◽  
pp. 177-227 ◽  
Author(s):  
P. Koumoutsakos ◽  
D. Shiels
Keyword(s):  
Flat Plate ◽  
Free Stream ◽  
Stokes Equations ◽  
The Body ◽  
Navier Stokes ◽  
Vorticity Field ◽  
Navier Stokes Equations ◽  
Unsteady Forces ◽  
Viscous Incompressible Flow ◽  
Experimental Works

The development of a two-dimensional viscous incompressible flow generated from an infinitesimally thin flat plate, impulsively started or uniformly accelerated normal to the free stream is studied computationally. An adaptive numerical scheme, based on vortex methods, is used to integrate the vorticity–velocity formulation of the Navier–Stokes equations. The results of the computations complement relevant experimental works while providing us with quantities such as the vorticity field and the unsteady forces experienced by the body. For the uniformly accelerated plate the present simulations capture the development of a number of centers of vorticity along the primary separating shear layer. This phenomenon has been observed in experimental works but has not been predicted by inviscid models. The present simulations suggest that this Kelvin–Helmholtz-type instability is driven by the interaction of primary and secondary vorticity near the tips of the plate and depends on the acceleration of the plate.

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