Transonic separation flow of water past a circular cone

The problem of subsonic, transonic, and supersonic separation flow of water past a circular cone of finite length is solved. The water is assumed to be an ideal compressible fluid. A steady flow picture is obtained in a process of stabilization with respect to the time by means of a two-dimensional finite-difference scheme [1]. The dependence of the drag coefficient on the Mach number of the oncoming flow, the distribution of the pressure over the conical surface, and the shape of the free surface formed behind the cone are investigated.     

Thermofluiddynamic experiments with a heated and rotating circular cylinder in crossflow

Heat transfer experiments with a heated and rotating circular cylinder in an air crossflow were performed for subcritical freestream-Reynolds-number 8.3 · 10³ < Re _f < 7.1 · 10⁴ and for Nusselt-numbers up to 300. The experiments took into consideration important practical parameters such as freestream-turbulence intensity, aspect ratio, blockage ratio and temperature loading. The measured values were standardized to the ‘idealized case’ to allow adequate comparison with pertinent literature. The results encompass the range of velocity ratios α (circular/freestream-velocity) between zero and 2.5. For values α > 0.5, the typical Nusselt-number behaviour noted by some authors has been confirmed. For small velocity ratios α < 0.5, however, there are significant deviations from the heat transfer coefficients previously believed to be constant.     

Transverse subsonic flow past a cylinder

At around the critical Reynolds number Re = (1.5–4.0)·10⁵ there is an abrupt change in the pattern of transverse subsonic flow past a circular cylinder, and the drag coefficient C_x decreases sharply [1]. A large body of both experimental and computational investigations has now been made into subsonic flow past a cylinder [1–4]. A significant contribution to a deeper understanding of the phenomenon was made by [4], which gives a physical interpretation of a number of theoretical and experimental results obtained in a wide range of Re. Nevertheless, the complicated nonstationary nature of flow past a cylinder with separation and the occurrence of three-dimensional flows when two-dimensional flow is simulated in wind tunnels do not permit one to regard the problem as fully studied. The aim of the present work was to make additional experimental investigations into transverse subsonic flow past a cylinder and, in particular, to study the possible asymmetric stable flow regimes near the critical Reynolds number.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 154–157, March–April, 1980.     

Thermofluiddynamic experiments with a heated and rotating circular cylinder in crossflow

Two-dimensional boundary layer profiles of heated and rotating circular cylinders in crossflow were investigated for subcritical freestream-Reynolds-numbersRe = 3.4 · 104 andRe = 4.8 · 10⁴. The peripheral speed of the cylinder surface corresponds to velocity ratios 0 ≦ ξ ≦ 2(α, circular/freestream-velocity). Special attention was focused on the location of separation points, which was determined as a function of the velocity ratio a whereby a strong influence of wall temperature was revealed.     

Transonic flow past a convex corner with free streamline

An asymptotic analysis in the limit of large Reynolds numbers Re → ∞ is made of the system of Navier—Stokes equations in the neighborhood of a corner in a profile past which there is a transonic gas flow. The flow with free streamline from the corner point at which the velocity of sound is reached is taken as a limiting case. In the first approximation, it is described by a self-similar solution to the Kármán—Fal'kovich equation with self-similarity exponent n = 6/5 [1]. In such a flow, the favorable pressure gradient becomes infinite as the corner is approached from the side of the oncoming flow.     

Calculation of spontaneously condensing steam flows in a plane turbine cascade

The results of a numerical analysis of stationary spontaneously condensing steam flows in a plane turbine cascade are presented and compared with the experimental and calculated results of other authors. The effect of the flow parameters on the position and strength of the condensation shocks is analyzed. The local and integral characteristics of superheated and wet steam flows are compared.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 144–153, November–December, 1995.     

Thermofluiddynamic experiments with a heated and rotating circular cylinder in crossflow

Two-dimensional flow fields and temperature boundary layer profiles around a heated and rotating circular cylinder in crossflow were experimentally investigated for a subcritical freestream-Reynolds-number 5.6 · 10⁴ corresponding to a flow velocity of 7 m/s. Test parameter was the ratio of free stream velocity to peripheral speed, which encompasses the range between zero and 2.5. An electronically-controlled hot wire measurement technique, practicable for the requirements of 1–2 mm boundary layer thickness, was used. The numerous reliable test results confirm previous reported experiments. Characteristic features in heat transfer are discussed.List of symbols C _b correction factor for blockage - n rotation rate in rpm - r radial coordinate - R cylinder radius - Re Reynolds-number = U 2R/v - Re _R circumferential Reynolds-number = U _R 2R/v - T local temperature - U velocity - = U · C _b/U _R velocity ratio of air flow and cylinder surface, corrected for blockage - v kinematic viscosity - = T — T /T _w — T non-dimensional temperature Indices undisturbed flow conditions - w wall - R circumferential - c critical Dedicated to Alfred Walz on the occasion of his 80th birthday     

Transonic flow past an airfoil with mini-flaps

The effect of mini-flaps located on either the lower or upper side of an airfoil near its trailing edge on the flow around the trailing edge and the global flow past the airfoil is numerically investigated. The flow pattern near the trailing edge is compared with that on which the Chaplygin-Joukowski hypothesis is based. The mini-flap effect on the aerodynamic characteristics of the airfoil is studied.     

Capillary cavity flow past a circular cylinder

Cavity flow past a circular cylinder is considered accounting for the surface tension on the cavity boundary. The fluid is assumed to be inviscid and incompressible, and the flow is assumed to be irrotational. The solution is based on two derived governing expressions, which are the complex velocity and the derivative of the complex potential defined in an auxiliary parameter region. An integral equation in the velocity magnitude along the free surface is derived from the dynamic boundary condition. The Brillouin–Villat criterion is employed to determine the location of the point of flow separation. The cases of zero surface tension and zero cavitation number are obtained as limiting cases of the solution. Numerical results concerning the effects of surface tension and cavitation development on the cavity detachment, the drag force and the geometry of the free boundaries are presented over a wide range of the Weber and the cavitation numbers.     

Numerical investigation of condensing steam flow in boundary layers

The paper describes a numerical method for the prediction of condensing steam flow within compressible boundary layers. The method is based on a simple stream function technique, which enables straightforward integration of the nucleation and droplet growth equations in a Lagrangian frame of reference. Calculations show how viscous dissipation and reduced expansion rate within a typical boundary layer influence nucleation and growth, leading to droplet radii and size distributions that differ substantially from those predicted in inviscid flow. The impact of condensation on temperature and velocity profiles, and the implications for thermodynamic loss are also considered.     

PIV measurements of flow past a confined cylinder

This study investigates the flow past a confined circular cylinder built into a narrow rectangular duct with a Reynolds number range of 1,500 ≤ Re _d ≤ 6,150, by employing the particle image velocimetry technique. In order to better explain the 3-D flow behaviour in the juncture regions of the lower and upper plates and the cylinder, respectively, as well as the dynamics of the horseshoe vortex system, both time-averaged and instantaneous flow data are presented for regions upstream and downstream of the cylinder. The size, intensity and interaction of the vortex systems vary substantially with the Reynolds number. Although the narrow rectangular duct with a single built-in cylinder is a geometrically symmetrical arrrangement, instantaneous flow data have revealed that the flow structures in both the lower and upper plate–cylinder junction regions are not symmetrical with respect to the centreline of the flow passage. The vortical flow structures obtained in side-view planes become dominant sometimes in the lower juncture region and sometimes in the upper juncture region in unsteady mode.     

Flow of rarefied gas past a sweptback cylinder

A numerical investigation has been made of the hypersonic flow of a rarefied monatomic gas past the windward part of the side surface of an infinite circular cylinder. The calculation was made by direct statistical Monte Carlo modeling for freestream Mach number M_t8=20, ratio of the surface temperature of the body to the stagnation temperature equal to t_tw =T _tw/T _t0 = 0.03, sweep angle 75°, and Reynolds number Re_t0 30.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 146–154, January–February, 1992.     

Nonuniqueness of the Transonic Flow past an Airfoil

The inviscid transonic flow past a symmetric airfoil having a curvature minimum in the middle is numerically investigated. It is shown that at zero angle of attack both symmetric and asymmetric steady-state flow patterns can exist on a certain freestream Mach number range M_min < M_max. On this range, the asymmetric flows are stable against small perturbations, whereas the symmetric flows are stable only if M does not coincide with a singular Mach number at which small variations in M or can result in flow restructuring.     

High-temperature oxidation of a zirconium cylinder in a steam atmosphere

The deformation of a solid cylinder with free ends is considered under isothermal oxidation conditions. The oxidation of the cylinder lateral surface is accompanied by the formation of stresses in the oxide (these stresses reach its ultimate compressive strength) and by the appearance of tensile stresses in the metal (these tensile stresses cause its creep). A condition of transition from the regime of protective oxidation to the regime of destructive oxidation is obtained.