Study of Dynamic Loads of Aircraft Bevel Gear Systems

This paper studies the dynamic loads of bevel gears with circular and straight teeth with the overlap factors less than two (ε_α < 2) and more than two (ε_α > 2). The advantages of the gears with straight teeth with ε_α > 2 are shown.     

The Stressed State of a Stiffened Conical Shell with Thermal Protective Coating with Temperature-Dependent Properties

The equations of the mathematical model are solved in terms of special functions. The results for the design scheme of the aircraft forebody are obtained with a guaranteed accuracy by the stable method of functional normalization.     

To Calculation of Regenerative Cooling of a Liquid Fuel Rocket Engine Chamber

This paper demonstrates that in transition from the one-dimensional longitudinal-channel motion of the coolant in the regenerative cooling system of the liquid propellant engine to the twodimensional (interchannel) channel motion (transpiration) through a porous mesh material (PMM), the hydraulic losses decrease. Experimental data on PMM hydraulic resistance coefficients and heat transfer in porous paths with the interchannel coolant transpiration (ICCT) is presented.     

Magnetic Field Amplification in Galaxy Clusters and Its Simulation

We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intra-cluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges.     

Application of a discrete-continuous model of strength analysis to solve the identification problem of a thermally loaded structure

This paper proposes to solve the problem of determining the strength properties of materials for thin-walled structural elements under mechanical and thermal loading as an optimization problem. A mathematical statement of the problem under certain assumptions is given.     

Discharges in the Stratosphere and Mesosphere

In the present paper salient features of discharges in the stratosphere and mesosphere (namely sprites, halos, blue starters, blue jets, gigantic jets and elves), are discussed. The electrostatic field due to charge imbalance during lightning processes may lead to stratospheric/mesospheric discharges either through the conventional breakdown based on streamers and leaders or relativistic runaway mechanism. Most (not all) of the observed features of sprites, halos and jets are explained by this processes. Development and evolution of streamers are based on the local transient electrostatic field and available ambient electron density which dictate better probability in favor of positive cloud-to-ground discharges, and thus explains the polarity asymmetry in triggering sprites and streamers. Elves are generated by electromagnetic pulse radiated by return stroke currents of cloud-to-ground/inter-cloud discharges. Generation of the both donut and pancake shape elves are explained. Electrodynamic features of thunderstorms associated with stratospheric/mesospheric discharges are summarized including current and charge moment associated with relevant cloud-to-ground discharges. The hypothesis relating tropospheric generated gravity waves and mesospheric discharges are also discussed. Finally some interesting problems are listed.     

Computational analysis of strength,stability, and durability for gas turbine engine exhaust frame

A computational technique, developed for analysis of strength, stability and low-cycle durability of GTE exhaust frame complex structure under operational and emergency loads is described. The presented technique, based on the ANSYS and STAR-CD engineering analysis software, and self-design software can improve the accuracy and efficiency of calculations, and reduce efforts on finite element mesh development, performing calculations and processing of results.