Steady Axial Flow Research Articles

Helical Flow through Concentric Annulus

The object of this investigation is to study the properties of a fully developed turbulent helical flow in a concentric annulus. A steady axial flow is assumed to take place under a constant axial pressure gradient with the inner cylinder of the annulus rotating at a constant angular velocity. The generalized eddy viscosity concept is used and the equations of motion, in cylindrical coordinates, are solved to obtain the axial and tangential velocity distributions. The results compare favorably with some existing experimental data. The results of the present study ultimately lead to the determination of the axial resistance to the flow and torque required at the inner cylinder of an annulus to maintain a uniform flow under any given condition.

Cylindrical flow of a fluid containing deformable structures

This is an investigation of the steady axial and angular flow of a non-rigid micro (structured) fluid in an infinitely long cylinder. The analytic solutions to the equations of motion obtained here reveal a number of interesting results. These include multimaxima velocity profiles, counter pressure gradient flow and velocity profiles similar to those for turbulent flow in a cylinder. Possible applications of the theory are discussed.

Cross-Velocity Behavior in Parallel Channel Flow

Exponential decay is found for cross flow velocities superimposed on steady, fully developed axial flows. Experimental data show that this type of flow may occur in the annular gap between fixed concentric cylinders. Here, a circumferential velocity, or cross flow, can exist in the presence of a steady axial flow, where a constant pressure difference is maintained between the ends of the cylinders. This flow field is investigated analytically by approximating the cylindrical surfaces by a pair of parallel walls, where the radii of the two cylinders are assumed to be much larger than the annular gap. Solutions to the Navier-Stokes equations are found for uniformly injected (axisymmetric) cross velocity profiles superimposed on parabolic axial velocity profiles. An approximate matrix method is used to formulate solutions for initially arbitrary cross velocity profiles. Results of the calculations show that the exponential decay of the cross flow becomes increasingly stronger as the axial flow rate is diminished. Experimental data obtained from the cylindrical flow model supported these predictions.

Slow Steady Axial Flow of a Rivlin‐Ericksen Fluid in a Wavy Annulus with Heat‐Transfer

AbstractThe problem of heat transfer due to the steady slow motion of a Rivlin‐Ericksen fluid in the annular space between two wavy cylinders has been considered. Taking the deformation of the boundaries to be small, the equations of continuity, momentum and energy have been solved using the perturbation technique. The solution for the velocity field is employed to study the nature of the temperature distribution under two types of thermal boundary conditions. Non‐Newtonian parameters affect the velocity field, the stresses and the temperature field. The flow pattern and the temperature distribution are somewhat similar in nature to that observed in case of the way cylindrical tube in reference [5].

Shock-flame interaction in a cylindrical chamber.

is produced toward the axis of the vortex along the wall. Since the fluid carried inward cannot accumulate at the attachment points without producing an unsteady change in the flow structure, the point of attachment at one end moves to a region where the ambient pressure is lower than it is at the other end and thus establishes a steady axial flow that removes the fluid brought to the axis at the high-pressure end. In the present case, a suitably low pressure for venting in this way is found near the edge of the hole on either side of the longitudinal axis and somewhat downstream of the center of the hole. Fig. 1 Streak photograph of a cylindrical flame taken across a 2-mm-wide, diametral slit. Equimolar acetylene-oxygen mixture at an initial pressure of 100 mm Hg is used.