in this present study, volume of fluid method in openfoam open source cfd package will be extended to consider phase change phenomena with modified model due to condensation and boiling processes. this model is suitable for the case in which both unsaturated phase and saturated phase are present and for beginning boiling and condensation process needn't initial interface. both phases (liqu...

in this research ideal magnetohydrodynamics equations (mhd) has been solved in a channel of quasi one dimensional plasma flow. magnetohydrodynamics equations, including continuity, momentum, energy and induced magnetic field equations are with the respect of the gauss magnetic condition. the implemented numerical solution is based on harten, lax, vanleer (hlld) discontinuities solution methods....

this research is carried out to design and manufacturing of lathe vibration tool and their tests. firstly, one-dimensional vibration tool is designed and made of the bending vibration mode. one-dimensional vibration tool with half piezoelectric rings is considered to excite the bending mode of tool. structure of vibration tool is designed in abaqus software about 20 khz and then is made with re...

We prove that the ENO reconstruction and ENO interpolation procedures are stable in the sense that the jump of the reconstructed ENO point values at each cell interface has the same sign as the jump of the underlying cell averages across that interface. Moreover, we prove that the size of these jumps after reconstruction relative to the jump of the underlying cell averages is bounded. Similar s...

and Applied Analysis 3 exist and are bounded for a self-adjoint positive operator A. Here B 1 2 ( τA √ A 4 τ2A ) , K ( I 2τA 5 4 τA 2 )−1 . 2.2 Theorem 2.1. For any gk, 1 ≤ k ≤ N − 1, and fk,−N 1 ≤ k ≤ 0, the solution of problem 1.2 exists and the following formula holds: uk ( I − R2N )−1{[ R − R2N−k ] u0 [ RN−k − R k ][ Pu0 − τ 0 ∑ s −N 1 P N−1Gfs μ ] − [ RN−k − R k ] I τB 2I τB −1B−1 N−1 ∑ s ...

‎‎‎In this paper‎, ‎we develop multi-step methods to solve a class of two-dimensional nonlinear Volterra integral equations (2D-NVIEs) of the first kind‎. ‎Here‎, ‎we convert a 2D-NVIE of the first kind to a one-dimensional linear VIE of the first kind and then we solve the resulted equation numerically by multi-step methods‎. ‎We also verify convergence and error analysis of the method‎. ‎At t...

The initial-value problem for hyperbolic equation d2u(t)/dt2 +A(t)u(t) = f (t) (0 ≤ t ≤ T), u(0) = φ,u(0) = ψ in a Hilbert space H with the self-adjoint positive definite operators A(t) is considered. The second order of accuracy difference scheme for the approximately solving this initial-value problem is presented. The stability estimates for the solution of this difference scheme are establi...

in recent years, the number of research works devoted to applying the highly accurate numerical schemes, in particular compact finite difference schemes, to numerical simulation of complex flow fields with multi-scale structures, is increasing. the use of compact finite-difference schemes are the simple and powerful ways to reach the objectives of high accuracy and low computational cost. compa...

a lattice boltzmann method is applied to demonstrate the comparison results of simulating natural convection in an open end cavity using different hydrodynamic and thermal boundary conditions. the prandtl number in the present simulation is 0.71, rayleigh numbers are 104,105 and 106 and viscosities are selected 0.02 and 0.05. on-grid bounce-back method with first-order accuracy and non-slip met...