Discussion: “Developing Region of Laminar Jets With Uniform Exit Velocity Profiles” (Rankin, G. W., and Sridhar, K., 1978, ASME J. Fluids Eng., 100, pp. 55–59)

1978 ◽  
Vol 100 (3) ◽  
pp. 374-375
Author(s):  
A. Mitsunaga
1981 ◽  
Vol 103 (2) ◽  
pp. 322-327 ◽  
Author(s):  
G. W. Rankin ◽  
K. Sridhar

An approximate solution to the velocity distribution in a submerged axisymmetric, laminar jet which issues from a long tube is presented. The solution is a modification of that of Okabe [17] and takes into account the changes that occur in the parabolic profile downstream of the jet exit. Comparisons are made with experimental data and other approximate theories taken from the literature.


1992 ◽  
Vol 114 (2) ◽  
pp. 191-197 ◽  
Author(s):  
R. K. Sullerey ◽  
V. Ashok ◽  
K. V. Shantharam

The present experimental investigations are concerned with diffusers employing the concept of vortex control to achieve high pressure recovery in a short length. Two types of two-dimensional diffusers have been studied, namely, vortex controlled and hybrid diffusers. Investigations have been carried out on such short diffusers with symmetrically and asymmetrically distorted inlet velocity profiles for area ratios 2.0 and 2.5 and divergence angle of 30 and 45 deg at a Reynolds number of 105. For each of the above configurations, experiments have been carried out for a range of fence subtended angles and bleed rates. The results indicate improvement in diffuser effectiveness up to a particular bleed off for both types of diffusers. It was observed that the nature of exit velocity profiles could be controlled by differential bleed.


Author(s):  
A. L. Brundage ◽  
M. W. Plesniak ◽  
S. Ramadhyani

Measurements were taken of the exit velocity and turbulence intensity distributions for film cooling holes fed from a narrow plenum above the middle jet in a row of five jets using hot-wire anemometry. Parameters varied in the experiments included the length-to-diameter ratio of the holes, the coolant-to-mainstream blowing ratio, the angle of inclination of the holes, and the plenum flow direction, which was either in the same direction as, or opposite to, the mainstream. Flow visualization within the film cooling holes and in the plenum revealed large secondary flow structures that affected the jet exit velocity distributions. The exit velocity profiles for short holes had “peaky” signatures associated with jetting in the upstream portion of the 35° holes and in the downstream portion of the 90° holes. For the longer holes, the exit velocity profiles were more uniform. Crossflow boundary layer fluid was found to enter into the film cooling holes in some short hole configurations. The coolant feed direction affects the details of the flow separation at the hole entrance and within the hole, and consequently influences the jet exit velocity profile. These effects are most pronounced for higher blowing ratios.


1978 ◽  
Vol 100 (1) ◽  
pp. 55-59 ◽  
Author(s):  
G. W. Rankin ◽  
K. Sridhar

The integral form of the momentum and energy equations, subject to the boundary layer simplifications, are used to obtain an approximate solution for an axisymmetric laminar jet with a uniform profile at the nozzle exit. The solution is expressed in a closed form. The jet flow field is divided into a developing and developed region. In the developing region a potential core is assumed to exist, bounded by an annular free shear layer, Schlichting’s velocity profile for an axisymmetric laminar jet is assumed in the free shear layer. The present solution is compared with existing experimental and analytical results in the developing region. Also a graphical method for determining the potential core radius and the parameters of the assumed Schlichting profile is given.


2008 ◽  
Vol 130 (10) ◽  
Author(s):  
V. Raghavan ◽  
B. Premachandran

Microscale gas flow through channels with a right-angled bend has been numerically analyzed to study the effect of the fillet radius on flow characteristics. The flow is assumed to be incompressible, laminar, and hydrodynamically developing. The fillet radius has been varied from zero, representing a sharp corner, to 0.6 times the height of the channel. The Knudsen number has been varied from zero, representing no-slip at the boundary, to 0.1, which is the limiting case for the slip-flow regime. A low Reynolds number of value 1 has been considered in the present study, which makes the flow to be within the incompressible slip-flow regime. The flow characteristics in terms of velocity profiles, velocity vectors, and the pressure ratio between the inlet and outlet of the channel have been presented for several cases. Results show that for the case of the fillet radius equal to zero, the flow separation occurs after the bend and due to this, the exit velocity profile changes significantly. The highest pressure ratio between the inlet and the outlet is required to maintain a specific mass flow rate for this case. The cases with a nonzero fillet radius exhibit exit velocity profiles identical to that of a straight channel. The pressure ratio decreases when the fillet radius and the Knudsen number are increased.


2015 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Yanuar Yanuar ◽  
Kurniawan T. Waskito ◽  
Gunawan Gunawan ◽  
Budiarso Budiarso

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