Different Values Of Angle Research Articles

Turbulent Study of Roll Pitch Yaw Phenomena for a Finned Store Released from a Wing Regarding Different Values of Angle of Attack

In this article, the commercial software CFD FASTRAN is applied to study the roll, pitch and yaw phenomena of turbulent flows around a finned store released from a wing regarding different values of angle of attack. The three-dimensional, unsteady Navier-Stokes equations and standard k-ɛ turbulent model are solved in the Cartesian coordinate system. The Chimera two-block grid system is utilized, and grid communication among two blocks are automatically implemented. To evaluate the accuracy of the present calculation, the calculated instantaneous trajectories of center of gravity of store, angles of roll, pitch and yaw, velocities and angular rates are compared with those of experimental data. The satisfactory agreement is achieved. Then, computations of different values of angle of attack applied on the store are carried out to investigate the unsteady roll, pitch and yaw phenomena of the separated store. Longitudinally clockwise roll angle of store from pilot's viewpoint and yaw angle toward the wing tip decrease as the angle of attack increases. Maximum value of pitch angle increases as the angle of attack increases, and the time of maximum value of pitch angle increases as well.

Effect of Angle of Incidence of Sun Rays on the Bending of Absorber Tube of Solar Parabolic Trough Concentrator

In a parabolic trough system, the solar flux distribution on the surface of absorber tube is non-uniform which results in circumferential temperature gradient. Thus, bending moment is induced and leads to the deflection in absorber tube from the focal line of trough. It is concluded that during zero angle of incidence of sun rays (angle made by sun rays with trough's aperture normal), absorber tube will not deflect from the focal line. However, during non-zero angle of incidence, the absorber tube will deflect. It is because of the fact that during non-zero angle of incidence, the absorber tube does not receive any concentrated flux near the end facing the sun. In the current work, an analytical expression is derived for finding the deflection in the central axis of absorber tube from the focal line of trough. Results for deflection are plotted for different values of angle of incidence taking the dimensions of LS3 parabolic trough with Schott 2008 PTR70 receiver.

Analysis of toughness on notched specimens by volumetric method

In the present work, an analysis of influence of the notch on the toughness of material KI is presented. A notched plate made out of structural steel is considered and subjected to uniformly tensile loading. Different values of angle and notch radius were selected. The material is assumed to be elastic perfectly plastic and the analysis was made according to a local approach defined by the volumetric approach. The parameters of the volumetric approach are the effective distance, effective stress and relative stress gradient and are determined by using the finite element method (F.E.M). The variation of the weight function affects the calculation of effective stress. The results obtained are confronted with models of Irwin and Creager - Paris. The results obtained show that for small radii, the stress intensity factor calculated by the weight function unit is close to those obtained by the models of Irwin and Creager-Paris. The increasing in the notch angle influences on the assessment of fracture toughness.

Computational Analysis of High Speed Flow Over a Conical Surface with Changing the Angle of Attack

The work to be presented herein is a numerical analysis of flow over a 20-degree half angle cone for compressible fluid, with Mach number of 2.5 with respect to different values of angle of attacks. The problem to be solved involves formation of shock waves so that the general characteristics of supersonic flow are explored through this problem. Shock waves and slip surfaces are discontinuities in fluid mechanics problems. It is essential to evaluate the ability of numerical technique that can solve problems in which shocks and contact surfaces occur. In particular it is necessary to understand the details of developing a mesh that will allow resolution of these discontinuitiesThe results of contour plots of pressure, temperature, density and Mach number with respect of angle of attack will show that CFD is capable of predicting accurate results and is also able to capture the discontinuities in the flow, e.g., the oblique shock waves. The global comparison between the numerical and the analytical values show a good agreement.

Magnetohydrodynamic spin waves in degenerate electron-positron-ion plasmas

Low frequency magnetosonic waves are studied in magnetized degenerate electron-positron-ion plasmas with spin effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, and spin magnetization energy, a generalized dispersion relation for oblique magnetosonic waves is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. For three different values of angle θ, the generalized dispersion relation is reduced to three different relations under the low frequency magnetohydrodynamic assumptions. It is found that the effect of quantum corrections in the presence of positron concentration significantly modifies the dispersive properties of these modes. The importance of the work relevant to compact astrophysical bodies is pointed out.

Stability and Flying Qualities of an Unmanned Airplane Using the Vortex-Lattice Method

The purpose of the present work is to evaluat e the static stability and open loop dynamic stability for un power ed condition of the Unmanned Aerial Vehicle for Ecological Conservation. Forces and moments were obtained by the vortex lattice method. These were computed for different values of angle of a ttack, sideslip angle, aileron, rudder and elevator deflection, and pitch, yaw and roll rates. Static stability and control derivatives were obtained and used for the analysis of airplane open loop dynamic stability and response. The longitudinal and later al –directional derivates show that the airplane is statically stable. The short period mode and phugoid mode correspond with damped mode. Dutch roll mode and roll mode of the airplane matches with damped mode and convergent mode, respectively. However, spi ral mode re spo nse prediction corresponds to a divergent mode. The airplane reaches flying qualities equal and better than those of Level 2

Magnetic field effects on two plasmon decay in a plasma

A high amplitude right circularly polarized (RCP) electromagnetic wave in a magnetized plasma parametrically decays into a pair of electrostatic waves. The prominent decay wave pairs are (i) two lower hybrid waves, (ii) two upper hybrid waves, and (iii) a lower hybrid wave and an upper hybrid wave. The phase matching conditions for these processes are satisfied over a wide range of plasma density, no longer restricting the parametric instability near the quarter critical density. However in the radial density profile produced by the pump wave with Gaussian distribution of intensity, only lower hybrid waves may get localized. The growth rate of each decay process is resonantly enhanced when the pump frequency is close to the electron cyclotron frequency. The growth rates for different channels maximize at different values of angles between the wave vectors of the decay wave and the static magnetic field.

Extension of theoretical considerations of the filling of pharmaceutical hard gelatin capsules to the design of dosator nozzles

A previous paper presented theoretically how the compressive stress, applied to a powder in a capsule-filling dosator nozzle to ensure retention, can be minimised. A theoretical method of reducing these stresses still further is proposed. This involves using a nozzle with two areas of different values of angle of wall friction φ. The main part of the nozzle should have a low value of φ, but the wall near the nozzle outlet, a high value of φ. This ensures that effective stress transmission to the nozzle outlet occurs with minimal frictional losses at the wall and that powder arching (and hence retention) is promoted by the rougher wall surface at the nozzle outlet. This in turn reduces the amount of stress required for arching to occur.

Effect of Submergence on Bearing Capacity

The effect of submergence of the soil below the foundation on the bearing capacity is analysed by the method of characteristics. The bearing capacity of strip footings are obtained using different densities in the calculations, the total unit weight for part of the failure zone above the ground water level and the submerged density for the portion of failure surface below the ground water level. The analysis is conducted for various depths of submergence of the soil and for different values of angle of internal friction. The results are presented in the form of charts which give the modified value of bearing capacity factor Nγ for typical values of unit weight, for angle of internal friction ranging from 15° to 40°.