The two – stage optimization technique applicable to helical wind turbine characteristics is considered. As an objective function at the first stage is selected the wind turbine power coefficient wich should be maximized. The maximal value of wind energy production per unit of rotor swept area is taken as an objective function at the second stage, when it is supposed, that wind turbine characteristics is optimally adapted to local wind conditions.
A numerical model to simulate the heat transfer in the grain heap heating was developed. This model is based on the 2-D equation of the heat transfer. The implicit scheme is used for the numerical simulation. The results of the numerical experiment are presented.
For modeling of amplitude-frequency characteristics of the liquid in the bath when gas, a simple mathematical model of pressurization and destruction tuyere bubble is proposed. Amplitude-frequency characteristics are obtained. It is shown that the frequency spectrum is a reflection of a variety of dynamic processes associated with the fluctuation margin and bubbles.
The plane problem of elasticity theory for a plate with a rigid inclusion is analyzed. The plate is under the action of load which is applied at interior points of the area. It is believed that the matrix in the vicinity of the inclusion vertices has detached from it. With the help of Fourier integral transforms the problem is reduced to a system of singular integral equations, numerical solution of which is obtained by using quadrature formula of Gauss-Chebyshev. The research covers the dependence of the length of the contact area on the mechanical properties of the material, the size and the load application points.
A problem concerning definition of stresses and displacements in the elastic plane with a circular inclusion and an arc crack at the material interface is considered under the loading applied at the crack and at infinity. The problem is reduced to the singular integral Fredholm equation of the second kind which is solved by series expansion in Jacobi polynomials. The expressions for stresses at the interface, crack opening and the stress intensity factors are found.
Problem concerning axial symmetric plane deformation of the multilayered ring has been considered. For some layers shear modulus changes continuously at the radial direction. Algorithm for evaluation stresses and displacements based on the use of compliance coefficients is proposed. Recurrent relationships are applied to determine the compliance coefficients.
Computing experiments to determine the hydrodynamic characteristics for bodies of revolution, which the most frequent as hydrodynamic devices, are conducted. Mathematically the problem reduces to determining the nature of shock interaction with large and small Froude numbers. The obtained hydrodynamic characteristics can be used in determining forces acting on devices located on the surface of the liquid.
Considered initial-boundary value problem of mathematical physics that describes the longitudinal fluctuations of the rope variable length with a weight at the lower end. Provides a comparison of solutions using a modified method of continuation and numerical integration.
In this paper, the problem of determining the position of the flow separation zone at the impact interaction of a solid and a liquid is reduced to the solution of the transcendental equation for the coordinates of the starting point of separation using Hadamard – Manglera formulas for obtained divergent integrals. The case of impact of horizontal plate compared with the analytical solution of the problem.
We consider the problem of determining the shell temperature at different heat transfer conditions when thermal parameters do not depend on temperature. Is taken into account the dependence of the total heat flux of temperature and time. Refined approximation a thin shell in the form of heat capacity Error of the solution is determined by the inverse heat conduction problem for a thin shell.
A nonlinear nonstationary problem of heat conduction for dissipative heating process in rod’s elements of constructions due to high cyclic loading is considered. The analytical solve with the same structure of the linear problem solving, taking into account the temperature dependences for thermomechanical properties of material and heat generation is obtained due to the method of successive intervals.
The numerical research of energy transfer in the solar photovoltaic module was completed. The temperature fields were defined on the basis of non-stationary conjugate two-dimension equitation of heat conduction. In the mathematic model accounted all significant geographical, climate and technology factors, whish influence in the energy parametric of the solar modules. The numerical research allowed to reveal general temperature regime of the systems and to formulate recommendations for its minimization.
A stress and deformable state near interface crack tip situated in anisotropic bimaterial space under concentrated load on a crack faces is considered. System of Gilbert problems is obtained and solved analytically. An influence of anisotropy of consisted materials on stresses and deformations is investigated.
The flow structures in two-dimensional and three-dimensional opened cavities without bottom above a screen with streamline of viscous incompressible flows are considered. The comparative analysis of kinematic and dynamic characteristics is carried out. Influence of space factor into flow structure in opened cavity without bottom above a screen are established.
In this article an analytical solution of the heat equation in one-dimensional formulation at the motion of two-phase evaporating coolant through the porous cylindrical channel at the boundary conditions of the first, second and third kind is derived . The resulting solution is compared with the existing solution for the flat channel. Produced the equation for calculating steam content in regard to the problem.
The different variants of theory which take into account the microstrain have been proposed, they evolved in many papers. And some of them have obtained completely experimental proof. The drawback was the lack of a clear passage to from viscoplastic to elastoplastic behavior. In this paper, we construct a viscoplastic tangent operator. It provides this transition and allows to construct the tangent stiffness matrix, which is necessary for solving the localization of irreversible deformation and fracture.
The problem of determining the stress-strain state of the elasticplastic beam with edge crack in a complex shift is considered and the influence of the loading history on the crack opening displacement is investigated.
Effective predictive model developed to study the dynamics of air pollution under emissions from automobile transport in the conditions of a "street canyon". The model is based on the combined solution hydrodynamic task with use of the model of vortex separated flows of an inviscid fluid and task of the distribution of gas emissions from automobile traffic. This predictive model can calculate the level of air pollution given the important factors: wind speed, atmospheric diffusion, building size, emission intensity. The numerical results and experimental researches are presented in the work. Using this model we can calculate the dispersion of emissions from automobile transport for «street canyon» using protective screens arranged along the highway.
A localization strip of plastic deformation between two materials assuming that the graph of intermaterial deformation has a peak-"tooth" is investigated. Dirichlet problem for a piecewise-analytic function is formulated and solved exactly. The numerical results of the length of localization strip of plastic deformation, shear displacement jumps and shear stress for various external loads and mechanical properties of materials are presented.
Objective of this work is development of the effective CFD model which can be used for prediction efficiency of the horizontal settlers with taking into account the geometrical form of the settler and the peculiarities of the sedimentation process. To simulate the process of the water purification in the horizontal settler the transport equation of pollutions and the equation of potential flow are used. To solve these equations Samarskii A.A. implicit difference scheme is used. On the basis of developed numerical model the code was created using FORTRAN language.
A numerical model was developed to simulate building protection from toxic chemical penetration using air jet. The model is based on the K-gradient model of pollutant dispersion and the model of the potential flow. The implicit schemes are used for the numerical integration. Results of numerical experiment are presented.
A CFD model to simulate the air ions concentration in rooms was developed. This model is based on the equations of the admixture dispersion and the model of potential flow. The implicit schemes are used for the numerical simulation. The results of the numerical experiment are presented.