Abstract. The Direct Simulation Monte-Carlo (DSMC) technique is used for numerical analysis of rarefied-gas hypersonic flows near a blunt plate, wedge, two side-by-side plates, disk, torus, and rotating cylinder. The role of various similarity parameters (Knudsen and Mach numbers, geometrical and temperature factors, specific heat ratios, and others) in aerodynamics of the probes is studied. Im...

To solve the problem of tension stress caused by centrifugal force and high-speed operation permanent magnet (PM) rotor, a FeCo-based PM rotor structure model is proposed. Based on thick-walled cylinder theory, uniform analytical calculation formulas strain field, displacement field are derived, stresses sleeve obtained. The correctness method (ACM) verified finite element (FEM). derived formul...

Conventional mechanical pumps based on centrifugal or axial turbomachinery are not suitable for micro and nano scales where the Reynolds numbers are usually small. Centrifugal and inertial forces are negligible, and viscous forces dominate the flow field in this length scale (an excellent review can be found on the physics of fluid flow at microscale in [1]). A microfluidic rotary pump, which i...

A numerical study of the onset of thermal convection in a rotating circular cylinder of radius-to-depth ratio equal to four is considered in a regime dominated by the Coriolis force where the onset is to so-called wall modes. The wall modes consist of hot and cold pairs of thermal plumes rising and descending in the cylinder wall boundary layer, forming an essentially one-dimensional pattern ch...

We examine the characteristics of helical flow in a concentric annulus with radii ratios of 0.52 and 0.9, whose outer cylinder is stationary and inner cylinder is rotating. Pressure losses and skin friction coefficients are measured for fully developed flows of water and a 0.4% aqueous solution of sodium carboxymethyl cellulose (CMC), when the inner cylinder rotates at the speed of 0~62.82 rad/...

Following recent works of several authors like Huilgol, Bhattacharya etd. and Javadpour et al., this paper is to contribute further to the literature of axial flow in a rotational coaxial rheometer. We consider axial flow of Herschel Bulkley mode1 between two concentric cylinders with the inner one rotating, while the outer cylinder is held stationary. An attempt has been made to direct the...

Laminar stagnation flow, axi-symmetrically yet obliquely impinging on a rotating circular cylinder, as well as its heat transfer is formulated as an exact solution of the Navier-Stokes equations. Rotational velocity of the cylinder is time-dependent while the surface transpiration is uniform and steady. The impinging stream is composed of a rotational axial flow superposed onto irrotational rad...

By theoretically analyzing dynamic behavior of the crankshaft, the rolling piston and the blade inrolling-piston rotary compressors, constraint forces and sliding speed at each pair of movable machine elements were obtained, and unbalanced inertia forces and compressor vibrations were evaluated. It was concluded that theoretical results have a goodagreement with experimental ones. Moreover, it ...

The onset of instability induced by impulsively started rotating cylinder was first investigated experimentally by Chen and Christensen [1]. The initial laminar flow evolves into a secondary flow pattern which consists of a series of Taylor-like vortices. In this transient boundary-layer system the critical time tc to mark the onset of secondary motion becomes an important question. This proble...