The Boundary Layer Inside a Conical Surface Due to a Swirling Flow With Throughflow

1976 ◽  
Vol 43 (4) ◽  
pp. 564-566 ◽  
Author(s):  
J. M. Fabian ◽  
G. C. Oates
Keyword(s):  
Boundary Layer ◽  
Entire Range ◽  
Close Agreement ◽  
Swirling Flow ◽  
Approximate Solutions ◽  
Conical Surface

The problem of describing the boundary layer existing inside a conical surface due to the presence of a swirling flow passing through the cone is considered. Approximate solutions based upon the Karman-Polhausen method are obtained for both the laminar and the turbulent cases. The results obtained are in close agreement with known solutions previously obtained in the limits of swirl with no throughflow and throughflow with no swirl. The present results appear to be valid over the entire range of swirl to throughflow ratios.

The Suppression of Flow Separation by Sequential Wall Jets

1976 ◽  
Vol 98 (3) ◽  
pp. 447-452
Author(s):  
P. North
Keyword(s):  
Boundary Layer ◽  
Fluid Flow ◽  
Kinetic Energy ◽  
Energy Flux ◽  
Close Agreement ◽  
Total Kinetic Energy ◽  
Wall Jet ◽  
Wall Jets ◽  
Single Jet ◽  
Flow Devices

The performance of many fluid flow devices is limited by the separation of the turbulent boundary layer. This separation may be suppressed or delayed by use of wall jets, raising questions of jet location and strength. A numerical analysis of a single wall jet gave results in close agreement with experiment. The same analysis of a single wall jet gave results in close agreement with experiment. The same calculation procedure indicated that two sequential wall jets, with the same total kinetic energy flux as the single jet, would suppress separation under conditions where the single jet would not. The best two-jet arrangement would be achieved with 63 percent of the total kinetic energy flux in the first jet. It is possible that three-jet arrangements could provide some further improvement.

scholarly journals Suction/Injection Effects on the Swirling Flow of a Reiner-Rivlin Fluid near a Rough Surface

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Bikash Sahoo ◽  
Sébastien Poncet ◽  
Fotini Labropulu
Keyword(s):  
Boundary Layer ◽  
Boundary Conditions ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Swirling Flow ◽  
Velocity Profiles ◽  
Partial Slip ◽  
Injection Velocity ◽  
Slip Boundary Conditions ◽  
Slip Boundary

The similarity equations for the Bödewadt flow of a non-Newtonian Reiner-Rivlin fluid, subject to uniform suction/injection, are solved numerically. The conventional no-slip boundary conditions are replaced by corresponding partial slip boundary conditions, owing to the roughness of the infinite stationary disk. The combined effects of surface slip (λ), suction/injection velocity (W), and cross-viscous parameter (L) on the momentum boundary layer are studied in detail. It is interesting to find that suction dominates the oscillations in the velocity profiles and decreases the boundary layer thickness significantly. On the other hand, injection has opposite effects on the velocity profiles and the boundary layer thickness.

Maximum and Average Flash Temperatures in Sliding Contacts

1994 ◽  
Vol 116 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Xuefeng Tian ◽  
Francis E. Kennedy
Keyword(s):  
Temperature Rise ◽  
Entire Range ◽  
Function Method ◽  
Approximate Solutions ◽  
Sliding Contact ◽  
Heat Sources ◽  
Flash Temperature ◽  
Infinite Body ◽  
Average Surface ◽  
Heat Partition

The surface temperature rise for a semi-infinite body due to different moving heat sources is analyzed for the entire range of Peclet number using a Green’s function method. Analytical and approximate solutions of maximum and average surface temperatures are obtained for the cases of square uniform, circular uniform, and parabolic heat sources. Considering the heat partition between the two contacting bodies, solutions of interface flash temperature are presented for the general sliding contact case as well as for the case of sliding contact between two moving asperities.

Swirling Flow in a Fixed Container: Generation and Attenuation of a Vortex Column

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Nahas ◽  
A. Calvo ◽  
M. Piva
Keyword(s):  
Boundary Layer ◽  
Swirling Flow ◽  
Vortex Formation ◽  
Fluid Motion ◽  
Bottom Boundary ◽  
Global Circulation ◽  
Columnar Vortex ◽  
Central Nozzle ◽  
Suction Flow ◽  
Vessel Bottom

The development of a columnar vortex and its attenuation using radial rods at the bottom boundary of a stationary container are experimentally studied. The fluid motion is achieved combining two independent flows: a global circulation around the cylinder axis and a meridian flow generated by recirculating fluid through a central nozzle located at the vessel bottom. The resulting velocity field is analyzed under two conditions: with and without the meridian or suction flow. It is shown that in the second condition a columnar vortex merges and that its intensity increases when the suction flow rate is increased. The key role played by the bottom boundary layer in the vortex formation is demonstrated. In the last part of the work, the attenuation of the vortex intensity produced by a set of rods located at the vessel bottom is investigated. It is found that obstacles with heights of the order of the boundary layer thickness are enough to produce the total annihilation of the vortex column.

The Laminar Boundary Layer on a Rotating Circular Arc Blade

1966 ◽  
Vol 88 (1) ◽  
pp. 111-120
Author(s):  
R. M. Halleen ◽  
J. P. Johnston ◽  
W. C. Reynolds
Keyword(s):  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Perturbation Technique ◽  
Approximate Solutions ◽  
Boundary Layer Separation ◽  
Primary Objective ◽  
Centrifugal Impeller ◽  
Pressure Gradients ◽  
Boundary Layer Problem ◽  
Rotating Blade

The primary objective was to develop an exact solution to the simplest possible laminar boundary-layer problem for a curved rotating blade. It was formulated initially so that the results might be used to illuminate some of the characteristics of boundary-layer behavior on centrifugal impeller blades. The solution was obtained by a perturbation technique and the results compared to existing approximate solutions and related exact solutions. A primary result shows that rotation itself may induce laminar boundary-layer separation on a blade trailing face in the absence of free-stream, longitudinal adverse pressure gradients. This result is then interpreted to show that such a separation may become important for impellers of low ReD = uˆtD/ν; i.e., when ReD ≤ 900.

INTEGRATED RESEARCHES OF ACOUSTICAL EXPOSURE ON GAS-DUST FLOW IN THE VORTEX-ACOUSTIC DISPERSER

2016 ◽  
Vol 2 (1) ◽  
pp. 155-161 ◽  
Author(s):  
Бойчук ◽  
Igor Boychuk ◽  
Перелыгин ◽  
Dmitriy Perelygin
Keyword(s):  
Boundary Layer ◽  
Acoustic Wave ◽  
Swirling Flow ◽  
Acoustic Effect ◽  
Dispersed Flow ◽  
Acoustic Impact ◽  
Dust Flow

The article deals with the movement of gas-dispersed flow in the chamber of vortex - acoustic dis-perser. The simulation of the acoustic impact on the course of the swirling flow. It is shown that the acoustic effect for a flow leads to its inhibition. At the same time for the flow in the boundary layer takes oscillatory. Modeling has allowed to establish the nature of the distribution of acoustic oscil-lations by using single and successive acoustic wave generators, enhances the effect of braking.

Boundary-layer velocity profiles in a swirling convergent flow field

1972 ◽  
Vol 52 (2) ◽  
pp. 357-367 ◽  
Author(s):  
T. M. Houlihan ◽  
D. J. Hornstra
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Swirling Flow ◽  
Theoretical Calculations ◽  
Experimental Investigations ◽  
Conical Nozzle ◽  
Flow Conditions ◽  
Boundary Layer Flows ◽  
Layer Velocity ◽  
Convergent Flow

Velocity distributions within the boundary layer of a swirling flow of incompressible fluid in a convergent conical nozzle have been investigated. Theoretical calculations with boundary conditions more appropriate to physically existent situations discounted the existence of 'super-velocities’ within the boundary layer. Parallel experimental investigations demonstrated an interdependence of core and boundary-layer flows which precluded the maintenance of the flow conditions required by the analysis.

Airfoils with separation and the resulting wakes

1986 ◽  
Vol 163 ◽  
pp. 323-347 ◽  
Author(s):  
Tuncer Cebeci ◽  
R. W. Clark ◽  
K. C. Chang ◽  
N. D. Halsey ◽  
K. Lee
Keyword(s):  
Boundary Layer ◽  
Conformal Mapping ◽  
Flow Separation ◽  
Close Agreement ◽  
Eddy Viscosity ◽  
Lift Coefficient ◽  
Inviscid Flow ◽  
Interaction Method ◽  
Large Flow

A viscous/inviscid interaction method is described and has been used to calculate flows around four distinctly different airfoils as a function of angle of attack. It comprises an inviscid-flow method based on conformal mapping, a boundary-layer procedure based on the numerical solution of differential equations and an algebraic eddy viscosity. The results are in close agreement with experiment up to angles close to stall. In one case, where the airfoil thickness is large, small difficulties were experienced and are described. The method is shown to be capable of obtaining results with large flow separation and quantifies the role of transition on the lift coefficient.

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