نتایج جستجو برای: moment equations method
تعداد نتایج: 1848949 فیلتر نتایج به سال:
Dilute gas-particle flows can be described by a kinetic equation containing terms for spatial transport, gravity, fluid drag, and particle-particle collisions. However, the direct numerical solution of the kinetic equation is intractable for most applications due to the large number of independent variables. A useful alternative is to reformulate the problem in terms of the moments of the veloc...
We consider condensing flow with droplets that nucleate and grow, but do not slip with respect to the surrounding gas phase. To compute the local droplet size distribution, one could solve the general dynamic equation and the fluid dynamics equations simultaneously. To reduce the overall computational effort of this procedure by roughly an order of magnitude, we propose an alternative procedure...
The moment method is a well known mode identification technique in asteroseismology (where ‘mode’ is to be understood in an astronomical rather than in a statistical sense), which uses a time series of the first 3 moments of a spectral line to estimate the discrete oscillation mode parameters l and m. The method, contrary to many other mode identification techniques, also provides estimates of ...
We suggest kinetic models of dissipation for an ensemble of interacting oriented particles, for example, moving magnetized particles. This is achieved by introducing a double bracket dissipation in kinetic equations using an oriented Poisson bracket, and employing the moment method to derive continuum equations for magnetization and density evolution. We show how our continuum equations general...
We investigate the dynamics of a deterministic finite-sized network of synaptically coupled spiking neurons and present a formalism for computing the network statistics in a perturbative expansion. The small parameter for the expansion is the inverse number of neurons in the network. The network dynamics are fully characterized by a neuron population density that obeys a conservation law analog...
planar d-bar integral equation is one of the inverse scattering solution methods for complex problems including inverse conductivity considered in applications such as electrical impedance tomography (eit). recently two different methodologies are considered for the numerical solution of d-bar integrals equation, namely product integrals and multigrid. the first one involves high computational ...
بررسی وجود و چندگانگی جوابهای معادلات دیفرانسیل به ویژه با شرایط مرزی اغلب بسی دشوار بوده و همراه با گام های ملالت آور می باشد بطوریکه همواره نیاز به پیش شرط هایی می باشد که معادلات دیفرانسیل با شرایط مرزی مورد نظر باید داشته باشد. بنابراین اثبات آنالیزی وجود و چندگانگی جوابهای مسائل مقدار مرزی غیر خطی اغلب غیر ممکن می باشد. روشهای تقریبی- تحلیلی یا روشهای عددی صرفاً برای بدست آوردن جواب موجود ...
A hierarchy of diffusive partial differential equations is derived by a moment method and a Chapman-Enskog expansion from the semiconductor Boltzmann equation assuming dominant collisions. The moment equations are closed by employing the entropy maximization principle of Levermore. The new hierarchy contains the well-known drift-diffusion model, the energy-transport equations, and the six-momen...
this paper presents the results of a study on the radiation characteristics of a plasma triangular antenna in the vhf band (30-300mhz) applying the method of moment. deriving the current distribution of the antenna, it shows the relationship between radiation characteristics of the plasma antenna and the plasma parameters. both theoretical and numerical results indicate that if the plasma frequ...
In this paper we present two methods for computing filtered estimates for moments of integrals and stochastic integrals of continuous-time nonlinear systems. The first method utilizes recursive stochastic partial differential equations. The second method utilizes conditional moment generating functions. An application of these methods leads to the discovery of new classes of finitedimensional f...
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