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For the complexity of calculating and analyzing the guided wave propagation and defect reflection in steel pipes, and the instructional role on studying the characters of T(0,1) mode guided wave to experimental studies, a method associating guided wave theory with numerical solution was applied to simulate T(0,1) mode guided wave propagation and defect reflection in steel pipes by building models,...
The flow field surrounding an underwater vehicle will change due to the influence from seabed terrains, when it navigates near seabed. The hydrodynamic coefficients of the underwater vehicle will change, and then produce a force and pitch moment, which could pull the underwater vehicle to the seabed. So it's very important for the safety of underwater vehicles while navigating near seabed to predict...
Thunderstorm downbursts are major cause of concern for engineering structures both on ground as well as those in air, namely aircrafts. The wind velocity profile of a thunderstorm downburst-induced wind is significantly different compared to natural atmospheric boundary layer winds. As a type of high intensity winds, thunderstorm microbursts have caused numerous structural failures around the world...
Based on the analysis of the principle of residual current device (RCD), the impact of sensitivity and unbalance response on the characteristics of residual current transformer (RCT) are discussed in detail. And a kind of RCT is designed by using analytical calculation and numerical simulation methods. Finally, a kind of RCD is developed in this paper. Experimental results show that the designed RCD...
Incentive Stock Option enterprises in developed countries has become the most effective means of encouragement, With the social development, China's domestic enterprises will be implemented gradually equity incentive system, Although only a small part of the company at this stage the implementation of the system, and from stock options trading there is still a long way. In the end of the stock options...
This paper, regarding high corrosion resistance cold precipitation circulation pump as the research subject, by means of numerical simulation study, analyse the inner fluid field with CFD software on the basis of k - ε turbulence model and unstructured grid SIMPLE algorithm. The results show that the internal flow rate, pressure distribution of the circulation pump could reveal the flow characteristics...
Through the analysis of the mechanism of soil arching effects of anti-sliding pile, using the plane finite element method, detailed analysis of the factors affecting soil arching effect, the results show: it is suitable when the space between two adjacent piles is 2.5-3.5 times than the pile diameter; the larger the pile diameter is, the less obvious soil arching effect is, as the increase of the...
Based on the structural features of projectile and concrete target, projectile damage mechanism and destroyed mode of target materials, utilizing the LS-DYNA which is a program that analyze dynamics to simulate the process of the target being intruded and damaged. The result is cohesive with theory and rules. At the same time, analyzing and validating the result by contrasting result and test result...
Based on the geological parameters of LIAOHE oil field, a numerical model with interlayer was established by computer, the STARS block of CMG was employed to simulate steam assisted gravity drainage (SAGD) with vertical and horizontal wells, the influences of interlayer on SAGD, the expansion process of steam chamber (SC) and the production index was obtained and analyzed. The results indicate: whether...
Network reliability is extensively used to measure the degree of stability of the quality of infrastructure services. In conventional network reliability theory, it is assumed that the exact value of each arc reliability are given. However, in many real world network it is difficult to estimate precise values of reliability. So a general fuzzy network model where reliability are presented as fuzzy...
An improving numerical method is provided in this paper for computing accurate Poincaré Map. Arc-Length integration was introduced and self-adaptive step-length control was developed for avoiding the error accumulation caused by a sharp turn of trajectory within one integration step. Numeric examples are also given, and numeric results demonstrate its accuracy and application.
In order to study on nonlinear vibration of current-carrying conductor, a differential equation is established by means of dynamics theory. Based on the method of multiple scales, the first approximate solution and corresponding solution of the primary parametric resonance is obtained. Numerical analysis results show that the amplitude and the topological structure changed with the increase of direct...
In this paper, the basic feature of particle system of coal stream is analyzed, the property model of coal stream particle is established by discrete element method according to its characteristics and a moving model is constructed by a simplified Hertz-Mindlin contact, and the coal stream movement is simulated with particle system, which plays an important role in assuring the fidelity and integrality...
Toward the ill-conditioned Problem of Gauss-Markov model, analyze the causes and all kinds of methods, emphatically research the computational process of Two-Step method. Extending and simplifying Two-Step method, give a new method for solving ill-conditioned problem, Matrix Parameterization method. Finally through analog computation, verify the feasibility and quality of Matrix Parameterization method.
The global dynamics of a periodic SIR epidemic model is investigated. The basic reproductive number Ro is dehed. It is proved that the disease-free equilibrium is globally stable if R0<;1. The disease-free equilibrium is unstable and the disease remains endemic when R0 > 1, The existence of the periodic solution is investigated and it is proved that the periodic model has at least one periodic...
In the present study, a series of terminal ballistics numerical analysis and experiments were performed to investigate the process for explosion load drive the based-water extinguisher dispersed. In the Numerical simulation, for the representative fire extinguishing warhead, the simulation model was built, The variety rule between the loading coefficient (drive charge divide liquid mass) and the breach...
According to the cavitation of centrifugal pump which produces in the condition of operating at off-design and inhale height exceeds the value of prescribed limit, the cavitation arouse pressure pulsation aggravate, so cause the performance of centrifugal pump that drops. Adopt RNG k - ε simulated technology model to study the relation between the pressure pulsation and cavitation of centrifugal pump,...
A Fourth-order compact finite alternating direction implicit difference scheme on the nine-points 2D stencil is formulated for solving the unsteady-state streamfunction-vorticity formulation of the Navier-Stokes/Boussinesq(N-S/B) equations. The unconditional stable numerical method is provided by alternating direction implicit difference method. Numerical solutions are obtained for the model problem...
In this paper, we have developed a pricing model for credit spread options with the existence of the counterparty default risk. The default dependence is modeled in the interacting intensities framework, and the correlation between default and the interest rate is considered. Semi-analytic pricing formulas for European credit spread put options with counterparty risk are derived. The numerical analysis...
Aimed at the typical problems for the arbitrary decision when choosing a value of slow-to-start probability, a value range analysis of slow-to start probability based on the cellular automata microsimulation is put forward, that is, in the two situations of considering and not considering the characteristics of cautious behavior, analyzing the influence of changing the slow-to-start probability to...
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