Journal of Applied Mechanics

Journal of Applied Mechanics
Author:
Publisher:
Total Pages: 1208
Release: 1972
Genre: Mechanical engineering
ISBN:

Publishes original research in all branches of mechanics including aerodynamics; aeroelasticity; boundary layers; computational mechanics; constitutive modeling of materials; dynamics; elasticity; flow and fracture; heat transfer; hydraulics; impact; internal flow; mechanical properties of materials; micromechanics; plasticity; stress analysis; structures; thermodynamics; turbulence; vibration; and wave propagation.

Asymmetric Entrainment of 2-D Curved Jets

Asymmetric Entrainment of 2-D Curved Jets
Author: Subrato Chandra
Publisher:
Total Pages: 192
Release: 1975
Genre: Aerodynamics
ISBN:

The control of VTOL aircraft during transition from hover to forward flight is complicated by the lifting jet-airframe interaction. This analysis is concerned with the entrainment aspect of two dimensional thick curved jets. A realistic mathematical model of such jets should account for different entrainment rates and the total pressure decay in the jet. The present theoretical analysis predicts curved jet characteristics needed for an accurate mathematical modelling of two dimensional lifting jets. The present analysis performs an integral method analysis of the curved jet using incompressible, fully turbulent, curved, free jet equations. Integral methods need specified jet edge velocity distributions. This streamwise velocity distribution depends on the airfoil geometry as well as on the jet. The present theory approximately retains this ellipticity by obtaining the streamwise jet edge velocities from a nonlinear iterative potential flow analysis of a thin jet issuing from the trailing edge of a hinged flat plate. The results of the present analysis are in agreement with available straight and curved jet results. The present theory predicts significantly (10%-20%) different entrainment rates near the exit where the curvature is maximum. Since V/STOL lift, moment, and pressure drag are significantly affected by the jet entrainment, one should incorporate the asymmetry of entrainment rates of curved thick jets in prediction methods. (Author).

Two-dimensional, Incompressible, Turbulent Curved-wall Jets

Two-dimensional, Incompressible, Turbulent Curved-wall Jets
Author: George Mon
Publisher:
Total Pages: 60
Release: 1973
Genre: Jets
ISBN:

NDS TO ATTACH ITSELF AND FLOW ALONG THE SURFACE. A theoretical and experimental study of the effects of the surface curvature on the flow field of a two-dimensional, incompressible, turbulent jet has been made. By using a perturbation technique, the governing equations for the flow have been obtained and solved numerically. There is flow similarity for a curved-wall jet when m = 1, and for the flow of a plane wall jet when the curvature approaches infinity. Two spiral and three circular cylindrical surfaces were tested. The mean velocity profiles and static pressure distributions were measured at various stations for each surface. In addition, the point of separation was found for Reynolds numbers, based on the nozzle width, in the range of 500 to 4000. The growth rates of the jet width and the rate of decay of the maximum velocity were deduced from the velocity measurements. (Modified author abstract).