Fluid dynamic effects of grooves on circular cylinder surface

AIAA Journal ◽  
1991 ◽  
Vol 29 (12) ◽  
pp. 2062-2068 ◽  
Author(s):  
Takeyoshi Kimura ◽  
Michihisa Tsutahara
Keyword(s):  
Circular Cylinder ◽  
Fluid Dynamic ◽  
Cylinder Surface ◽  
Dynamic Effects

A Model for Vortex Induced Oscillation of Structures

1974 ◽  
Vol 41 (3) ◽  
pp. 581-586 ◽  
Author(s):  
W. D. Iwan ◽  
R. D. Blevins
Keyword(s):  
Experimental Data ◽  
Circular Cylinder ◽  
Analytical Model ◽  
Vortex Shedding ◽  
Fluid Dynamic ◽  
Model Parameters ◽  
Structural Systems ◽  
Dynamic Effects ◽  
Hidden Variable ◽  
Model Predictions

A model is presented for the analysis of the response of structural systems excited by vortex shedding. The model is based on the introduction of a hidden variable to describe the fluid dynamic effects. Model parameters may be determined from experimental data for fixed and forced elements and the model used to predict the response of elastically mounted elements. Analytical model predictions are compared with experimental results for a circular cylinder.

Potential Flow Solution for Crossflow Impingement of a Slot Jet on a Circular Cylinder

1976 ◽  
Vol 98 (2) ◽  
pp. 249-255 ◽  
Author(s):  
H. Miyazaki ◽  
E. M. Sparrow
Keyword(s):  
Boundary Layer ◽  
Nusselt Number ◽  
Circular Cylinder ◽  
Potential Flow ◽  
Closed Form Solution ◽  
Form Solution ◽  
Stream Velocity ◽  
Cylinder Surface ◽  
Stagnation Region ◽  
Flow Solution

A closed-form solution has been obtained for the potential flow about a circular cylinder situated in an impinging slot jet. Among other results, the potential flow solution yields the free stream velocity for the boundary layer adjacent to the cylinder surface. A basic feature of the solution is the division of the flow field into subdomains, thereby making it possible to employ harmonic functions that are appropriate to each such subdomain. The boundary conditions on the free streamline and the conditions of continuity between the subdomains are satisfied by a combination of least squares and point matching constraints. Numerical evaluation of the solution was carried out for cylinder diameters greater or equal to the nozzle width and for a range of dimensionless separation distances between the nozzle and the impingement surface. Results are presented for the velocity and pressure distributions on the cylinder surface, for the position of the free streamline, and for the velocity gradients at the stagnation point. The latter serve as input information to the Nusselt number and skin friction expressions that are given by boundary layer theory. Comparisons were made with available experimental results for the pressure distribution, velocity gradient, and Nusselt number, and good agreement was found to prevail in the stagnation region.

scholarly journals PC206. A Novel Computation Model of the Carotid Artery to Determine Fluid Dynamic Effects on Plaque Instability

2016 ◽  
Vol 63 (6) ◽  
pp. 217S
Author(s):  
Kristy Cosgrove ◽  
Scott J. Hymel ◽  
T. Cooper Woods ◽  
Damir B. Khismatullin ◽  
Hernan Bazan
Keyword(s):  
Carotid Artery ◽  
Fluid Dynamic ◽  
Dynamic Effects ◽  
Computation Model ◽  
Plaque Instability

scholarly journals The Investigation of Mutual Interference Vortex Flow around Two Circular Cylinders by Flow Visualization and Pressure Measurement

2019 ◽  
Vol 291 ◽  
pp. 02001
Author(s):  
Yoshifumi Yokoi ◽  
Rut Vitkovičová
Keyword(s):  
Circular Cylinder ◽  
Pressure Measurement ◽  
Pressure Coefficient ◽  
Visual Observation ◽  
Mutual Interference ◽  
Circular Cylinders ◽  
Cylinder Surface ◽  
Visualization Experiment ◽  
Flow Apparatus ◽  
Measurement Experiment

In order to understand the aspect of the mutual interference flow from two circular cylinders, the visual observation experiment and the pressure measurement experiment were performed by use a water flow apparatus. Two circular cylinders with a diameter of D=10mm were used, and they have been arranged at staggered or tandem. The flow velocity was U=0.25m/s (Re=UD/í, í is kinematic viscosity of fluid). The dye oozing streak method was used in the visualization experiment. In the pressure measurement experiment, the pressure on the surface of a circular cylinder was detected by the single tube manometer, and measurement was performed by image processing using a computer. As a result, distribution of the circular cylinder surface pressure coefficient CP corresponding to the flow pattern and it in each circular cylinder arrangement was obtained. The drag coefficient CD was calculated from the pressure coefficient CP, and change of the resistance in each arrangement was found.

Control of Vortex Shedding Using a Screen Attached on the Separation Point of a Circular Cylinder and Its Effect on Drag

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Gokturk Memduh Ozkan ◽  
Erhan Firat ◽  
Huseyin Akilli
Keyword(s):  
Circular Cylinder ◽  
Surface Area ◽  
Vortex Shedding ◽  
Control Method ◽  
Separation Point ◽  
Whole Body ◽  
Cylinder Surface ◽  
Control Effect ◽  
Permeable Plate ◽  
Turbulent Statistics

The control of flow in the wake of a circular cylinder by an attached permeable plate having various porosity ratios was analyzed experimentally using both particle image velocimetry (PIV) and dye visualization techniques. The force measurements were also done in order to interpret the effect of control method on drag coefficient. The diameter of the cylinder and length to diameter ratio of the plate were kept constant as D = 50 mm and L/D = 1.0, respectively. The porosity ratio, β, which can be defined as the ratio of open surface area to the whole body surface area, was taken as β = 0.4, 0.5, 0.6, 0.7, and 0.8 (permeable plates). The study was performed considering deep water flow conditions with a constant Reynolds number of ReD = 5000 based on the cylinder diameter. Each permeable plate was attached on the separation point and the results were compared with the results of cylinder without permeable plate (plain cylinder) in order to understand the control effect. Both qualitative and quantitative results revealed that the permeable plates of 0.4 ≤ β ≤ 0.6 are effective on controlling the unsteady flow structure downstream of the cylinder, i.e., the vortex formation length was increased, turbulent statistics was reduced and vortex shedding frequency was diminished when the permeable plate attached normal to the cylinder surface from the lower separation point. However, the drag force acting on the cylinder was found to be increased due to the increased cross-sectional area.

Sign in / Sign up

Export Citation Format

Share Document