We investigate experimentally the causes of jet plume instability and enhanced mixing observed in the exhaust of shock-containing convergent-divergent nozzles. Key features of the internal flow are the separation shock, separation shear layers, and pattern of alternating expansion and compression waves downstream of the shock. We focus on two possible reasons for this instability—the motion of ...

This work considers the instability of the jet plume from an overexpanded, shockcontaining convergent-divergent nozzle and attempts to correlate this instability to internal shock-induced separation phenomena. Time resolved wall pressure measurements and Pitot measurements are used as primary diagnostics. For the conditions of this study flow separation is asymmetric resulting in a large separa...

Flight tests recently completed at the NASA Dryden Flight Research Center evaluated performance of a hydromechanically vectored axisymmetric nozzle onboard the F-15 ACTIVE. A flight-test technique whereby strain gages installed onto engine mounts provided for the direct measurement of thrust and vector forces has proven to be extremely valuable. Flow turning and thrust efficiency, as well as no...

Pelton turbine is the most commonly used high head impulse turbine with low discharge. For obtaining highest power output from runner one of the most important parameter is quality of jet which strikes bucket tangentially. The quality of jet and its impact work depends on the distance between the nozzle exit and runner along with its angle of strike. In the present paper, the effect of distance...

CFD is a branch of Fluid Mechanics which rely on numerical methods and algorithms to solve and analyze problem that involves fluid flow. CFD analysis has been conducted to analyze flow pattern of supersonic rocket nozzle at various degree of divergent angle by using two dimensional axis-symmetric model, which solves governing equation by a control volume method. Variation in parameters like vel...

Unstable mold flow could induce surface velocity and level fluctuations, and entrain slag, leading to surface defects during continuous casting of steel. Both argon gas injection and ElectroMagnetic Braking (EMBr) greatly affect transient mold flow and stability. Part I of this two-part article investigates transient flow of steel and argon in the nozzle and mold during nominally steady-state c...

In this paper, we construct various special solutions on a convergent-divergent surface for the steady compressible complete Euler system and established the stability of the purely subsonic flows. For a given pressure p0 prescribed at the “entry” of the surface, as the pressure p1 at the “exit” decreases, the flow patterns on the surface change continuously as those happen in a de Laval nozzle...

We present systematic studies on the absolute density of hydrogen cluster beams produced by using Laval-nozzles. Measurements of the cluster beam density as function of the nozzle temperature and the gas input pressure result in maximum cluster beam densities for cases where the gas is already in a supersaturated state before passing the nozzle. The influence of the gas flow through the nozzle ...

Distributions of nitric oxide vibrational temperature, rotational temperature and velocity have been measured in the hypersonic freestream at the exit of a conical nozzle , using planar laser-induced fluorescence. Particular attention has been devoted to reducing the major sources of systematic error that can affect fluorescence temperature measurements, including beam attenuation, transition s...

The flow structure obtained when Localized Arc Filament Plasma Actuators (LAFPA) are employed to control the flow issuing from a perfectly expanded Mach 1.3 nozzle is elucidated by visualizing coherent structures obtained from Implicit Large-Eddy Simulations. The computations reproduce recent experimental observations at the Ohio State University to influence the acoustic and mixing properties ...