scholarly journals Mean pressure distributions and reattachment lengths for roof-separation bubbles on low-rise buildings

2016 ◽  
Vol 155 ◽  
pp. 115-125 ◽  
Author(s):  
Abul Fahad Akon ◽  
Gregory A. Kopp
Keyword(s):  
Pressure Distributions ◽  
Separation Bubbles ◽  
Mean Pressure

An Investigation of the Forces on Three Dimensional Bluff Bodies in Rough Wall Turbulent Boundary Layers

1977 ◽  
Vol 99 (3) ◽  
pp. 503-509 ◽  
Author(s):  
B. E. Lee ◽  
B. F. Soliman
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Bluff Bodies ◽  
Drag Forces ◽  
Pressure Distributions ◽  
Mean Pressure ◽  
Flow Phenomena ◽  
The Mean ◽  
Building Ventilation ◽  
Group Density

A study has been made of the influence of grouping parameters on the mean pressure distributions experienced by three dimensional bluff bodies immersed in a turbulent boundary layer. The range of variable parameters has included group density, group pattern and incident flow type and direction for a simple cuboid element form. The three flow regimes associated with increasing group density are reflected in both the mean drag forces acting on the body and their associated pressure distributions. A comparison of both pressure distributions and velocity profile parameters with established work on two dimensional bodies shows close agreement in identifying these flow regime changes. It is considered that the application of these results may enhance our understanding of some common flow phenomena, including turbulent flow over rough surfaces, building ventilation studies and environmental wind around buildings.

Flow Past Circular Cylinder With Different Surface Configurations

1992 ◽  
Vol 114 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Y. C. Leung ◽  
N. W. M. Ko ◽  
K. M. Tang
Keyword(s):  
Reynolds Number ◽  
Groove Surface ◽  
Number Range ◽  
Pressure Distributions ◽  
Downward Shift ◽  
Reynolds Number Range ◽  
Lower Reynolds Number ◽  
Smooth Cylinder ◽  
Mean Pressure ◽  
The Mean

Measurements of the mean pressure distributions and Strouhal numbers on partially grooved cylinders with different groove subtend angles were made over a Reynolds number range of 2.0×104 to 1.3×105 which was within the subcritical regime of smooth cylinder. The Strouhal number, pressure distributions, and their respective coefficients were found to be a function of the groove subtend angles. In general, a progressive shift of the flow regime to lower Reynolds number was observed with higher subtend angle and a subtend angle of 75 deg was found for optimum drag reduction. With the configuration of asymmetrical groove surface, lower drag, and higher lift coefficients were obtained within the same Reynolds number range. Wake traverse and boundary layer results of the asymmetric grooved cylinder indicated that the flows at the smooth and groove surfaces lied within different flow regimes and a downward shift of the wake.

scholarly journals Leading Edge Separation Bubbles on Turbomachine Blades

1993 ◽  
Author(s):  
R. E. Walraevens ◽  
N. A. Cumpsty
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbine Blades ◽  
Leading Edge ◽  
Freestream Turbulence ◽  
Compressor Blades ◽  
Pressure Distributions ◽  
Quantitative Measurements ◽  
Small Influence ◽  
Separation Bubbles

Results are presented for separation bubbles of the type which can form near the leading edges of thin compressor or turbine blades. These often occur when the incidence is such that the stagnation point is not on the nose of the aerofoil. Tests were carried out at low speed on a single aerofoil to simulate the range of conditions found on compressor blades. Both circular and elliptic shapes of leading edge were tested. Results are presented for a range of incidence, Reynolds number and turbulence intensity and scale. The principal quantitative measurements presented are the pressure distributions in the leading edge and bubble region, as well as the boundary layer properties at a fixed distance downstream where most of the flows had reattached. Reynolds number was found to have a comparatively small influence, but a raised level of freestream turbulence has a striking effect, shortening or eliminating the bubble and increasing the magnitude of the suction spike. Increased freestream turbulence also reduces the boundary layer thickness and shape parameter after the bubble. Some explanations of the processes are outlined.

scholarly journals Wind effect on staggered cylinders of square and rectangular sections with variable longitudinal spacings

1970 ◽  
Vol 38 ◽  
pp. 52-57 ◽  
Author(s):  
MKM Hossain ◽  
MQ Islam ◽  
AC Mandal ◽  
S Saha
Keyword(s):  
Cross Sections ◽  
Cross Flow ◽  
Wind Effect ◽  
Total Force ◽  
Upstream Side ◽  
Pressure Distributions ◽  
Square Cylinders ◽  
Rectangular Cylinder ◽  
Identical Dimension ◽  
Mean Pressure

An experimental investigation of mean pressure distributions on a group of cylinders with square and rectangular cross-sections in a uniform cross flow is presented here. The group consists of one rectangular and two square cylinders of identical dimension. The rectangular cylinder is placed centrally in the upstream side and the other two square cylinders are placed symmetrically in the downstream side with respect to tunnel axis. Surface pressure distributions on the cylinders are measured for various longitudinal spacings of the cylinders. Wind loads are obtained in terms of drag coefficients, lift coefficients and total force coefficients. The drag on an isolated cylinder is higher in general than that on the same cylinder while it becomes part of a group. Keywords: Wind load, staggered cylinders. DOI: 10.3329/jme.v38i0.901 Journal of Mechanical Engineering Vol.38 Dec. 2007 pp.52-57

The effects of surface roughness on the flow past circular cylinders at high Reynolds numbers

1982 ◽  
Vol 123 ◽  
pp. 363-378 ◽  
Author(s):  
Y. Nakamura ◽  
Y. Tomonari
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
High Reynolds Number ◽  
Circular Cylinders ◽  
Similarity Parameter ◽  
Number Range ◽  
Pressure Distributions ◽  
Mean Pressure ◽  
Supercritical Range ◽  
High Reynolds

Measurements of’ the mean-pressure distribution and the Strouhal number on a smooth circular cylinder, circular cylinders with distributed roughness, and circular cylinders with narrow roughness strips were made over a Reynolds-number range 4.0 × l04 to 1.7 × l06 in a uniform flow. A successful high-Reynolds-number (trans- critical) simulation for a smooth circular cylinder is obtained using a smooth circular cylinder with roughness strips. High-Reynolds-number simulation can only be obtained by roughness strips and not by distributed roughness. A similarity parameter correlating the pressure distributions on circular cylinders with distributed roughness in the supercritical range is presented. The same parameter can also be applicable to the drag coefficients of spheres with distributed roughness.

Mean pressure distributions around a circular cylinder in the branch of a T-junction with/without vanes

2015 ◽  
Vol 88 ◽  
pp. 82-93 ◽  
Author(s):  
Bo Wu ◽  
Yantao Yin ◽  
Mei Lin ◽  
Liangbi Wang ◽  
Min Zeng ◽  
...  
Keyword(s):  
Circular Cylinder ◽  
Pressure Distributions ◽  
Mean Pressure

Leading Edge Separation Bubbles on Turbomachine Blades

1995 ◽  
Vol 117 (1) ◽  
pp. 115-125 ◽  
Author(s):  
R. E. Walraevens ◽  
N. A. Cumpsty
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Free Stream ◽  
Turbine Blades ◽  
Leading Edge ◽  
Compressor Blades ◽  
Free Stream Turbulence ◽  
Pressure Distributions ◽  
Small Influence ◽  
Separation Bubbles

Results are presented for separation bubbles of the type that can form near the leading edges of thin compressor or turbine blades. These often occur when the incidence is such that the stagnation point is not on the nose of the aerofoil. Tests were carried out at low speed on a single aerofoil to simulate the range of conditions found on compressor blades. Both circular and elliptic shapes of leading edge were tested. Results are presented for a range of incidence, Reynolds number, and turbulence intensity and scale. The principal quantitative measurements presented are the pressure distributions in the leading edge and bubble region, as well as the boundary layer properties at a fixed distance downstream, where most of the flows had reattached. Reynolds number was found to have a comparatively small influence, but a raised level of free-stream turbulence has a striking effect, shortening or eliminating the bubble and increasing the magnitude of the suction spike. Increased free-stream turbulence also reduces the boundary layer thickness and shape parameter after the bubble. Some explanations of the processes are outlined.

Module Friction Factors and Intramodular Pressure Distributions for Periodic Fully Developed Turbulent Flow in Rectangular Interrupted-Plate Ducts

1988 ◽  
Vol 110 (2) ◽  
pp. 147-154 ◽  
Author(s):  
R. K. McBrien ◽  
B. R. Baliga
Keyword(s):  
Turbulent Flows ◽  
Static Pressure ◽  
Rectangular Cross Section ◽  
Reynolds Numbers ◽  
Plate Spacing ◽  
Pressure Distributions ◽  
Geometric Configurations ◽  
Friction Factors ◽  
Mean Pressure ◽  
Fully Developed Turbulent Flow

This paper presents detailed time-mean pressure measurements for periodic fully developed turbulent flows in straight interrupted-plate ducts of rectangular cross section. Several combinations of plate spacing and duct aspect ratio are investigated for Reynolds numbers, based on a module hydraulic diameter, in the range 5000 to 45000. The experiments undertaken in this work establish the existence of steady, time-mean, periodic fully developed flows for all flow rates and geometric configurations investigated. The results include graphical and tabular presentations of module friction factor versus Reynolds number data, and intramodular time-mean wall static pressure distributions. The physical implications of these results are also discussed.

Sign in / Sign up

Export Citation Format

Share Document