numerical diffusion 中文意思是什麼
numerical diffusion
解釋
數植擴散-
For the diffusion model and numerical simulation model, the numerical character of chaff clouds during diffusion is obtained
對擴散模型進行分析得到了箔條雲團擴散過程中的數字特徵。 -
The diffusion model and numerical simulation model for chaff clouds are modeled on the assumption that the speed of air where chaff locates is a winner random process and the mass of chaff is zero so it can trace the atmosphere speed very well
摘要假定箔條所在位置處大氣運動速度是一個維納隨機過程，同時在忽略箔條的質量時箔條的運動完全反應當地大氣的運動，在此基礎上建立箔條雲團的擴散模型及數值模擬模型。 -
Using a dissolved conservative material as a tracer in the water, a three - dimension advection - diffusion water exchange numerical model was used to study the flushing time by discharge and the discharge dominated region of the yangtze estuary. the flushing time of the yangtze estuary is an important eigenvalue, which denotes the water environmental capability of estuary
然後應用以溶解態的保守性物質做為研究長江口水體交換的載體，建立了完全三維對流擴散型的長江口水體交換的數值模型，對長江口的水體交換時間做了一個整體的計算。 -
Using a dissolved conservative material as a tracer in the water, a three - dimension advection - diffusion water exchange numerical model was used to study the flushing time by discharge and the discharge dominated region of the yangtze estuary based on the successful simulation of flow field
在成功模擬長江口流場的基礎上，同時應用以溶解態的保守性物質做為長江口水體交換的載體，建立了三維對流擴散型的長江口水體交換的數值模型，對整個長江口的水體交換規律進行了研究。 -
Numerical simulation results indicate that, for low temperature dust particles, dust particles mainly exist in the area near the column center and their charge - number can be considered as a constant, while in the area where there are no dust particles, ion and electrons are in ambipolar diffusion ; for high temperature dust particles, both the distribution regions of dust particle and high ion density are expanded and dust charge - number is increasing with the distance from the center
計算結果表明：當塵埃粒子的溫度較低時，塵埃粒子主要集中在圓柱形放電器的中心很小的區域，塵埃粒子攜帶的電荷幾乎是一個常數，受塵埃粒子空間電荷的影響，離子在該區域的密度最高。在遠離中心區域，離子和電子呈現雙及擴散特點；當塵埃粒子的溫度較高時，塵埃粒子分佈的區域和高離子密度區域擴大，塵埃粒子離放電器中心越遠，攜帶的負電荷越多。 -
An intelligent numerical forecast on heavy gas diffusion process of hydrocarbon
智能化烴類重氣泄散過程的數值預測 -
Abstract : a technical concept, “ reverse source quantity ”, based on artificial neural network, has been pointed out in order to carry out a numerical dynamic simulation on hydrocarbon diffusion process
文摘:提出實現烴類重氣泄散態勢的動態過程數值預測新構想基於人工神經網路的「反求源」技術。 -
In the suspended sediment transport model, the method of shear stress is adopted to determine the source function in the suspended sediment diffusion equation. through a series numerical experiments and statistical analyses of observed field data, a local coefficient, which can reflect the bottom material and consolidation, is introduced into the classic critical erosion velocity of the sediment
懸沙輸運模型利用切應力方法來確定對流擴散方程中的泥沙源函數，其中的臨界起動速度利用經典的泥沙起動流速公式前面增加一個局地系數得到，這個系數能反映河床底質結構及固結程度，通過系列數值試驗和實測資料的統計分析確定。 -
Theoretical analysis and numerical experiments show that the improved nine - point scheme not only has completely overcome the second drawback mentioned above that the original nine - point scheme can not apply to the parabolic problem with diffusion coefficient drastically varying, but also has partly improved the applicability of the scheme when performed over irregular grids
（ 2 ）針對九點格式的上述缺點提出了改進方案。改進后的九點格式完全克服了原格式不適用於熱傳導系數劇烈變化的拋物問題的缺點，同時部分改善了該格式對不規則網格的適應性問題。 -
Thus, the conclusion is drawn : when the diffusion coefficient of cf is invariable and the diffusion time is under a certain range, the beginning corrosion time of the steel in the corner of the rectangular section is independent of the size of rectangular section ; ( 4 ) through the numerical value calculation of rectangular section, the law is found of the influence on modifying coefficient of rectangular section of the thickness of protection layer of concrete and diameter of the steel and the thickness of cf on the surface of concrete, based on which practical calculating method of beginning corrosion time of the steel in the corner of rectangular section is set up
從而得到結論：在氯離子擴散系數一定的情況下，在一定時間范圍內，矩形截面邊角區域鋼筋的初始銹蝕時間不依賴于矩形截面的截面尺寸； （ 4 ）通過矩形截面邊角區域鋼筋初始銹蝕時間的計算，分析了保護層厚度、鋼筋直徑、混凝土表面氯離子濃度對修正系數的影響，並在此基礎上建立了氯離子侵蝕下矩形截面邊角區域鋼筋初始銹蝕時間的實用計算方法。 -
Many factors regarding the modifying coefficients of circular and rectangular section are analyzed : ( 1 ) it is theoretically proved that the diffusion coefficient of cl - in concrete is dependent of modifying coefficients ; ( 2 ) through analysis of the results of numerical value calculation, it is discovered that the relation between the modifying coefficients and the thickness of protection layer of concrete is linear, from which the function expression of these two variables is gain ; at the same time, the influence on modifying coefficient of the radius of circular section and the thickness of cl - on the surface of concrete ; based on these, practical calculating method of beginning corrosion time of steel of circular section is set up ; ( 3 ) to rectangular section, the diffusion of cf in concrete is two - dimension diffusion
討論了影響矩形截面以及圓形截面修正系數的因素： （ 1 ）從理論上證明了氯離子在混凝土中的擴散系數與修正系數無關； （ 2 ）通過圓形截面數值計算結果的分析，發現圓形截面修正系數與保護層厚度基本成線性關系，並建立了二者之間的聯系；分析了圓形截面半徑、混凝土表面氯離子濃度對修正系數的影響，從而建立了圓形截面鋼筋初始銹蝕時間的實用計算方法； （ 3 ）在矩形截面氯離子侵蝕下，混凝土處於二維擴散狀態。本文通過計算分析，證明二維擴散的影響區域從邊角開始向中間逐步擴散，並證明了二維擴散影響區域依賴于氯離子擴散系數與氯離子擴散時間的乘積。 -
( 5 ) discuss some mathematical models of the pollutant transport problems in some local river flow fields. by integral transform method, the paper establishes the usual finite difference approximation scheme to solve the numerical solutions and gives examples for the computation of the approximating solutions, moreover, discusses one - dimensional characteristic finite difference method for a convection - diffusion equation under usual conditions
（ 5 ）針對水域中污染物輸移問題的數學模型，通過積分變換法，得到了簡化模型在理想化條件下的近似精確解，同時給出數值算例，並且對非理想化條件下模型的特徵差分方法進行了討論。 -
Experiment and numerical simulation of gas diffusion in utility tunnels
管廊內燃氣泄漏擴散的模型試驗與數值模擬 -
A propbr data structure is used to assist grid generation for different geometric dimensions. a concept of entropy in broad sense is proposed for convective - diffusive problems in chapter 7. it is proved that there is an intrinsic relationship between the stability of the numerical schemes of the convective - - diffusive differential equations and the non - negative property of the entropy generation caused by the effective diffusion
第七章提出了對流擴散問題中的廣義熵概念，研究了擴散熵產非負性特徵與數值格式穩定性的內在聯系，分析證明了擴散熵產非負定性及統計非負定性的穩定性準則，探討了穩定性與模擬性之間的矛盾與聯系。 -
Progress of the research in the area of numerical simulation of transient liquid phase diffusion bonding
瞬間液相擴散連接過程數值模擬的研究進展 -
Abstract : in this paper, we proposed a diffusion equation for simulating the problem of pollution, and discussed its application to point pollution, especially while instantaneous point pollution happened. finally, we gave the numerical analysis
文摘:給出了一個適合於模擬污染問題的擴散方程，討論了它在點污染，尤其是在瞬時點污染發生時的應用.並對一些實際算例進行了分析 -
Differential arithmetic is utilized to set up the numerical value arithmetic of the diffusion model of circular and rectangular section ; at the same time, the stability of the numerical value arithmetic is analyzed ; 4
利用差分演算法，建立了圓形截面以及矩形截面氯離子擴散模型的數值解法，並對數值演算法的穩定性進行了分析； 4 -
In this paper a numerical method for equations of transport and biodegradation in the fractured media is discussed. because the equations consist of terms related to advection, diffusion, biochemical as well as the term of exchange betwen the fracture and the porous media, it is very difficult to find their solution. in order to find more efficient method for solving these equations, several numerical methods for the equations without biochemical terms are discussed first. the numerical results show that the cubic spline method can be used to solve advection flow dominated problem which often occurred in the fractured media. then, the equation with both advection - diffusion term and biochemical term are discussed. the splitting - operator is used to decouple the advection and diffusion terms with biochemical term in the equations. the way to determine the smaller time step for solving fast biochemical terms is introduced through comparing the order of characteristic time of biochemical term with that advection ( diffusion ) term. numerical simulation results show that good agreement between analytical solution and experiment result is attained
本文討論了含裂隙介質地下水污染物輸運與生物降解非線性方程組數值求解方法.方程含有對流項、擴散項、生長、死亡、吸附、解吸、趨化和孔隙與裂隙介質界面間的交換項的非線性偶合，使演算法十分困難.本文討論了無生化過程時的幾種求解方法，數值結果表明：用三次迎風插值法對常見的對流項占優勢，且場變量有較大梯度的問題較適用.在討論有生化反應過程時，利用對流項與生化反應項的特徵時間量級估算，給出了求生化過程作用子步的時間步長估算辦法.用上述方法所得到的模擬結果與解析解、無化學反應和有化學反應的實測值對比，吻合很好 -
The characteristic approximation is used to handle the convection part along the direc - tion of fluid namely characteristic direction to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion ; the mixed finite element spatial approximation is employed to deal with diffusion part and approximate the scalar unknown and the adjoint vector function optimally and simultaneously ; in order to preserve the integral conservation of the method, we introduce the modified characteristic method
該方法對方程的對流部分沿流體流動的方向即特徵方向離散以保證格式在流動的鋒線前沿逼近的高穩定性，消除數值彌散現象；對方程的擴散部分採用最低次混合有限元方法離散、同時以高精度逼近未知函數及未知函數的梯度；為保證方法的整體守恆性，在格式中引入修正項 -
The new method is a combination of characteristic approximation to handle the convection part, to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion, a smaller time truncation is gained at the same time, and a mixed finite element spatial approximation to deal with the diffusion part, the sealer unknown and the adjoint vector function are approximated optimally and simultaneously
此方法即為對方程的對流項沿流體流動的方向即特徵方向進行離散，從而保證格式在流動鋒線前沿逼近的高穩定性，消除了數值彌散現象，並得到了較小的時間截斷誤差；另一方面，對方程的擴散項採用混合元離散，可同時高精度逼近未知函數及其伴隨向量函數，理論分析表明，此方法是穩定的，具有最優的l ~ 2逼近精度。
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