Microbursts have been simulated and studied using different physical and numerical modeling methods. In the present study, the steady impinging jet model was comprehensively studied by using a 2-footdiameter (0.61 m) microburst simulator available in the Department of Aerospace Engineering at Iowa State University. Point measurements and Particle Image Velocimetry (PIV) results revealed a detai...

A method for the simultaneous measurement of velocity and passive scalar concentration fields by means of particle image velocimetry (PIV) and planar laser induced florescence (PLIF) techniques is described here. An application of the combined PIV-PLIF system is demonstrated by performing simultaneous velocity and concentration measurements in the near field of a turbulent jet mixing flow. The ...

We present an analytical model for the cross section of a turbulent, radiative jet or wake. This model is appropriate for modeling HH jets, or “wakes” left behind by “astrophysical bullets”. Even though the model is very simple, it has the benign property of only having four free parameters (the outer radius of the beam, the axial velocity, the velocity at the edge of the beam, and the turbulen...

air-jet weaving is an advanced weaving method with high efficiency and productivity. it is one of the most widely used methods of weaving in the world. in air-jet filling insertion, the motion of weft yarn is caused by friction between weft yarn and air blown through nozzle. after declamping and subjecting the yarn to air stream, its motion is not active but very complicated and influenced by s...

The influence of convection and temperature on the radiation impedance of an open duct termination exhausting a hot gas is commonly described by a complex theory. A simplified analytical expression is proposed for low frequencies. Both models assume a free jet with uniform velocity bounded by infinitely thin shear layers. The convective velocity that should be assumed when applying these models...

The objective of this study is to compare the performance of different k-ε models, i.e. the Standard k-ε, the Renormalization Group (RNG) k-ε, and the Realizable k-ε, with a two-layer model for the prediction of the mean velocity field and the temperature pattern from a newly designed impinging jet supply device for ventilation of an office room. The numerical predictions are validated against ...

A t the impact of a plunging liquid jet with a receiving pool, air bubbles may be entrained if the impact velocity exceeds a critical velocity. New experiments were performed in a two-dimensional plunging jet. The ̄ ow conditions near the inception of air entrainment were investigated. Two mechanisms of air entrainment were visualized at low jet velocities: by elongated air cavity and by foam bu...

SUMMARY The linear spatial stability of a mixing layer between two parallel streams is considered, and a comparison is made between the stability of flows with and without a stationary splitter plate separating them upstream. The assumed velocity profile satisfies the condition of no slip on the splitter plate, but in other respects the flow is treated as inviscid. Account is taken of the jet s...

Published data on unconfined plane-wall jets and plane-free jets were reviewed and used to assess the accuracy of numerical simulations, A plane-free jet was numerically simulated using the standard k-e model and four nonuniform grid patterns (70 x32,100 x52,120 x 60, and 120 x 74), The solution for a plane-free jet with adequate grid resolution was in good agreement with the published data, A ...