A fourth order nonlinear evolution equation, which is a good starting point for the study of nonlinear water waves of wave-steepness up to 0.25, is used here to investigate the effect of randomness on stability of deep-water surface gravity waves in the presence of wind blowing over water. A spectral transport equation for narrow band Gaussian surface wave is derived. With the use of this transport equation stability analysis is made for an initial homogeneous wave spectrum having a very simple normal form to small oblique long wave length perturbations for a range of spectral widths. An expression for the growth rate of instability is obtained, in which higher order contribution comes from only one of the fourth order terms in the evolution equation, which is responsible for wave-induced mean flow. This higher order contribution in this expression for growth rate of instability produces a decrease in the growth rate. The growth rate of instability is found to decrease with the increase of spectral width and ultimately the instability disappears if the spectral width increases beyond a certain critical value, which is not influenced by the fourth order terms in the evolution equation.

     The stability of a horizontal fluid layer bounded on either side by porous layers with different permeabilities is examined for different non-uniform basic temperature gradients using general velocity and thermal conditions at the boundaries. In the case of sudden heating and cooling, analytical solutions are obtained using single-term Galerkin expansion. Numerical solutions are obtained for all possible combinations of basic temperature gradients and boundary conditions in respect of velocity and temperature. General conclusion about the thermal depth and the destabilizing effects of the basic temperature gradients are presented. The classical results of free-free, rigid-free and rigid-rigid boundaries with isothermal or adiabatic boundaries are recovered as limiting cases of the present study.

     This paper presents a residual stress analysis and plastic zone behavior in antisymmetric aluminum metal-matrix laminated plates. First-order shear deformation theory and Finite Element Method are considered in the solution for small deformations. The plate is meshed into 64 elements and 289 nodes with both simply supported or clamped boundary conditions. Stainless steel fiber reinforced aluminum metal-matrix laminated plates of constant thickness are formed by stacking four layers bonded antisymmetrically. It is assumed that the laminated plates are subjected to transverse uniform loads. Loading is gradually increased from yield point of the plate as 0.0001 MPa at each load step. Load steps are chosen as 100, 150 and 200.

     A free convection flow of a second order liquid past an impulsively started vertical plate in the presence of a transverse magnetic field has been studied in this paper. The solution has been obtained by finite-difference method. The effect of the parameters m (magnetic field strength), Pr (Prandtl number), Gr (Grashof number, Gr>0, cooling of the plate by free convection, Gr<0, heating of the plate by convection currents), E (the Eckert number) and 'alpha' (the elastic parameter) on the velocity, temperature and the skin friction has been shown through several graphs and tables.

     This paper analyses the stability characteristics of oil journal bearings considering the effect of elastic distortion on the surface of bearing liner and variation of viscosity of oil due to pressure. The theoretical analysis is intended to show how the effects of elastic distortion on the journal bearing performance can be calculated for three-dimensional bearing geometries. The deformation equations for bearing surface are solved simultaneously with hydrodynamic equations including variation of viscosity of oil, equation of motion to predict theoretically the fluid film pressure distribution and the journal orbit under dynamic condition. A non-linear analysis determines the locus of the journal for the operating conditions. The stability of the system can be determined from the journal locus.

     The role of spreading during SHS surfacing of the protective coatings has been investigated theoreticaly and experimentally. The case, when spreading of large drops is forced by the effect of gravity and the interface forces are low, is considered. Analytical and numeric solutions of the problem have shown that the ratio of the specific times of cooling and spreading is the main parameter, which determines the dynamics and the final characteristics of spreading. It has been shown that the process of spreading is most strongly affected by the initial melt mass and drop size, the activation energy of viscosity, and gravitation (microgravitation and overload) within these specific times. The experimental research into SHS surfacing has confirmed the theoretical data.

     The present study is devoted to investigating the influences of magnetic field on buoyancy induced flow over vertical flat plate embedded in a non-Newtonian fluid saturated porous medium. The Ostwald-de Waele power-law model is used to characterize the non-Newtonian fluid behavior. A similarity solution for the transformed governing equations is obtained with a prescribed variable surface heat flux. Numerical results for the details of the velocity and temperature profiles are shown on graphs. Excess surface temperature has been presented for different values of the power-law index n, magnetic parameter Mn^* and the exponent 'lambda'.

     The paper deals with three collinear Griffith cracks propagating with constant velocity under antiplane shear stress at the interface of an elastic layer of finite thickness h and a semi-infinite half plane of different elastic properties. The Fourier transform technique is used to reduce the elastodynamic problem to the solution of a set of integral equations which has been solved by using the finite Hilbert transform technique and Cooke's result. The analytical expressions for the stress intensity factors at the crack tips and crack opening displacements are obtained for large h. The graphical plots of these results are also presented for some particular cases.

     The dynamic rupture process of a thin liquid film on a cylinder has been analyzed by investigating the stability under the influence of a non-uniform electrostatic field to finite amplitude disturbances. The dynamics of the liquid film is formulated using the balance equations including a body force term due to van der Waals attractions. The effect of the electric field is included in the analysis only in the boundary condition at the liquid vapor interface. The governing equation for the film thickness was solved by finite difference method as part of an initial value problem for spatial periodic boundary conditions. The electric field stabilizes the film and increases the time to rupture when a long wavelength perturbation is introduced.

     The conventional design of building frames is based on the assumption that the settlement of footings has no effect on the load of the corresponding columns. In reality, the differential settlements among various footings result in a redistribution of the column loads, the amount of which depends on the rigidity of the structure and the load-settlement characteristics of the soil. The present paper attempts to study the effect of the same on design force quantities for frame members of building frames with isolated footings. The nonlinear settlement versus stress relationship arising in case of building frames with isolated footings on clayey soils is attempted to be dealt with two alternative iterative approaches. Results of a few simple three-dimensional frames obtained by the simpler approach are compared with the results of the more rigorous approach and found to be satisfactory. Frames resting on sandy soil are also studied by idealising the soil medium below the footing as linear elastic springs. Various representative case studies are presented for frames resting on sandy and clayey soil. These case studies may help in arriving at design provisions to account for such effects. The simpler iterative approach may be exercised with the help of available commercial frame analysis software and may prove useful in improved design of buildings accounting for the effect of soil-structure interaction. Adequacy of providing tie beams, continuous lintels, and diagonal braces in minimising the redistribution of force quantities are also studied and presented in the paper in limited form. The addition of diagonal braces are found to be effective in substantially minimising the change in force quantities due to the soil-structure interaction.

     A 2-dimensional computational fluid dynamics analysis of steady state thermal boundary layer flow of a second order non-Newtonian fluid past a horizontal wedge in a Brinkman-Darcy porous medium, in the presence of a transverse magnetic field, is presented. The governing equations are transformed from Cartesian coordinates (x,y) into a sixth order system of partial differential equations in a 'ksi'-n coordinate system. These complex equations are then reduced to a set of six first order equations which are solved using the robust Keller finite difference method, and a block tridiagonal iterative solver, SOLV6. It is shown that heat transfer magnitude is depressed by magnetic field parameter (Hartmann number, Ha) and also considerably reduced with increasing viscoelasticity parameter (K). Surface shear stresses are also reported to fall considerably with increase in viscoelasticity of the fluid. Effects of other hydrodynamic and thermal parameters on the flow are discussed in detail.

     In this paper, the basic processes accompanying a shock initiation of a detonation have been analyzed theoretically using numerical methods. The detailed discussion of initiation of a detonation by nonstationary shock waves generated by a solid body impact or explosively driven inertial partition is presented. The physical-mathematical model applied here comprises the set of equations of gas-dynamics, the elastic-plastic, and elastic/viscous-plastic theory. The additional elements of the model are constitutive relations rendering properties of materials and semi-empirical model of chemical reactions. In order to study these problems, the time dependent one- and two-dimensional fluid-dynamic equations have been numerically integrated for specific initial conditions. One-dimensional code is based on finite difference method. The two-dimensional numerical code is based on so called free particle method (HEFP - model). One of the fundamental questions answered is whether or not a stationary detonation wave will result from the given initial parameters. The better understanding of the nonstationary phenomena has been achieved, particularly at the transient processes preceding formation of a detonation wave. A phenomenon of generation of retonation wave was explained.

     In this paper, we point out local similarity transformations for the flow through a medium with high porosity bounded by a semi-infinite horizontal plate when the free stream velocity is of exponential form.