The mechanism of conversion from the kinetic energy of electron beams to electromagnetic wave energy is investigated in the two-stream amplifier. It is shown that the optimal efficiency of the amplifier scales according to AV/V for relativistic electron beams and (AV/V) 2 for nonrelativistic electron beams, where AV is the axial velocity difference in the two beams and V is the mean axial beam ...

A mathematical study on creeping flow of non-Newtonian fluids (power law model) through a nonuniform peristaltic channel, in which amplitude is varying across axial displacement, is presented, with slip effects included. The governing equations are simplified by employing the long wavelength and low Reynolds number approximations. The expressions for axial velocity, stream function, pressure gr...

Flow of a polymer in an intermeshing co-rotating twin-screw extruder is simulated. Effect of elongational viscosity on the flow is analyzed using independent powerlaw models for the shear and elongational viscosities. Axial component of the velocity is found to be maximum in the intermeshing region of the extruder. Axial component of velocity, which determines the throughput of the extruder, de...

A mathematical model is constructed to study the effect of heat transfer and elasticity of flexible walls in swallowing of food bolus through the oesophagus. The food bolus is supposed to be Jeffrey fluid and the geometry of wall surface of oesophagus is considered as peristaltic wave. The expressions for temperature field, axial velocity, transverse velocity and stream function are obtained un...

An optical method was used to determine the axial velocity of plasma jets produced by a DC plasma spray torch. Different experimental conditions were tested in order to systematically study the influence of the working parameters on the plasma velocity. In this way, the arc current ranged between 200 and 600 A, the gas flow rate between 30 and 80 slm, and the internal nozzle diameter between 6 ...

lin apparatus ,·,hieh could produce known amounts of angular momenlum in a pipeline was verified by direct measurement of axial and tangential velocity profiles. By using the assumption that a vortimetcr, with vanes spanning only the rotational core, responded to an equivalent solid rotational core, an expression was develop­ ed relating the angular velocity to the angular momentum. Comparison ...

We have carried out maps of microwave lines of 8 different molecules (12CO(2-1 and 1-0), 13CO(2-1 and 10), SiO(5-4), HCO+(1-0), SO2(100,10-91,9), CS(5-4), HCN(1-0) and HNC(1-0)) in OH 231.8+4.2, a protoplanetary nebula that shows a particularly rich molecular emission. Confirming previous observations, the total molecular extent is comparable to the optical image and the lines show a total velo...

Laminar fully developed ow and pressure drop in linearly varying cross -section converging-diverging microtubes have been is investigated in this work. These microtubes are formed from a series of converging-diverging modules. An analytical model is developed for frictional ow resistance assuming parabolic axial velocity pro le in diverging and converging sections. Frictional ow resistance is f...

In the present investigation we have studied the peristaltic flow of a couple stress fluid in a non-uniform rectangular duct. The flow is investigated in a wave frame of reference moving with the velocity c away from the fixed frame. The peristaltic waves propagating on the horizontal side walls of a non-uniform rectangular duct is studied under lubrication approach. The exact solutions of velo...

This paper pRisents nwneric:a.l analysis of the incompressible turbulent flow field in a single cavity of the stepped multi-cavity seal. The dimensionless bulk pressure drop for the cavity with and without groove has been investigated for four different Reynolds numbers and three different shaft ro~ating speeds. SIMPLER algoritlun is applied to solve the NavierStokes equation and lowReynolds nu...