Flow Induced by the Impulsive Motion of an Infinite Flat Plate in a Dusty Gas

Flow Induced by the Impulsive Motion of an Immite Flat Plate in a Dusty Gas. The problem of flow induced by an infinite flat plate suddenly set into motion parallel to its own plane in an incompressible dusty gas is of considerable physical interest in its own right as well as because of its close relation to the non-linear, steady (constant-pressure) laminar boundary layer. Its solution provides complete and exact information about modifications of the boundary layer growth and skin friction due to particle-fluid interaction. Moreover, it provides a basis for judging the accuracy of approximations which have been employed in more complex problems of viscous fluid-particle motion. The uncoupled thermal Rayleigh problem for small relative temperature differences is directly inferred and this answers questions about the modifications of the surface heat transfer rate and about the possibility of similarity with the velocity boundary layer. Similarity is possible when, in addition to a Prandtl number of unity, the streamwise relaxation processes are also similar

Penetration depth time history measurement method

A new method for measuring the depth time history of rigid body penetration into brittle materials under a deceleration of ~10^5 g. The method includes: sabot-projectile, sabot-projectile separation and penetration depth detection systems. Relatively small intrinsic time error (3%) and depth error (0.3–0.7 mm) results. Penetration depth time history in a series of 4140 steel projectile penetrations into a mortar are measured at velocities of 100 to 500 m/sec with sufficient accuracy such that differentiation with respect to time yields stopping force, via Newton's second law

On radiative transfer in the low Reynolds number blunt body stagnation region at hypersonic speeds. Part 1 - Emission dominated case

Effect of radiative heat transfer in low Reynolds number hypersonic flow about blunt bod

Distributed parameter type of control for a bilinear system

Optimal control laws for bilinear system in distributed parameter model - analytical determinatio

Comparison of uniform perturbation solutions and numerical solutions for some potential flows past slender bodies

Approximate solutions for potential flow past an axisymmetric slender body and past a thin airfoil are calculated using a uniform perturbation method and then compared with either the exact analytical solution or the solution obtained using a purely numerical method. The perturbation method is based upon a representation of the disturbance flow as the superposition of singularities distributed entirely within the body, while the numerical (panel) method is based upon a distribution of singularities on the surface of the body. It is found that the perturbation method provides very good results for small values of the slenderness ratio and for small angles of attack. Moreover, for comparable accuracy, the perturbation method is simpler to implement, requires less computer memory, and generally uses less computation time than the panel method. In particular, the uniform perturbation method yields good resolution near the regions of the leading and trailing edges where other methods fail or require special attention

The acoustic monopole in motion

The results of an experiment are presented in which a small monochromatic source which behaves like an acoustic monopole when stationary is moved at a constant speed over an asphalt surface past stationary microphones. An analysis of the monopole moving above a finite impedance reflecting plane is given. The theoretical and experimental results are compared for different ground to observer heights, source frequencies, and source velocities. A computation of the effects of source acceleration on the noise radiated by the monopole is also presented