共查询到19条相似文献,搜索用时 57 毫秒
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在奇异摄动数值法用于冶金过程中,提出了板坯连续铸锭在结晶器中凝固传热的一种数值模拟方法。把连续铸锭结晶部分的传热模型归结为一边界层型奇异摄动问题,并用奇异摄动数值方法进行了分析计算,得出了结晶器内铸坯的温度分布,液相穴宽度,坯壳厚度等参数。 相似文献
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本文研究奇摄动拟线性系统边值问题#br#εY"=F(t,y,ε)Y'+g(t,y,ε),(0≤t < 1)#br#Y(0,ε)=A(ε),Y(1,ε)=B(ε)#br#其中,Y,g,A,B都是n维向量,F(t,Y,ε)是n×n阶对角短阵,Y',Y"是关于变量t的导数。 相似文献
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用奇异摄动法解圆柱体的凝固问题 总被引:7,自引:0,他引:7
在求解伴随凝固和熔融的热传导问题时,本文试用一种奇异摄动方法,选择显热与潜热之比—Ste数为摄动参数,将温度、移动的固液界面位置以及时间按摄动参数的幂级数展开,求得了初态在熔点,表面因对流冷却而凝固的热传导问题的一阶近似解;给出了凝固总时间与Ste数以及Bi数之间的良好近似公式.所得结果与基用于焓模型求得的数值解和实验结果相符得很好. 相似文献
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Asymptopic solution for a class of semilinear singularly perturbed fractional differential equation 下载免费PDF全文
This paper considers a class of boundary value problems for the semilinear singularly perturbed fractional differential equation.Under the suitable conditions,first,the outer solution of the original problem is obtained;secondly,using the stretched variable and the composing expansion method the boundary layer is constructed;finally,using the theory of differential inequalities the asymptotic behaviour of solution for the problem is studied and the uniformly valid asymptotic estimation is discussed. 相似文献
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A singularly perturbed reaction diffusion problem forthe nonlinear boundary condition with two parameters 下载免费PDF全文
A class of singularly perturbed initial boundary value
problems of reaction diffusion equations for the nonlinear boundary
condition with two parameters is considered. Under suitable
conditions, by using the theory of differential inequalities, the
existence and the asymptotic behaviour of the solution for the initial boundary
value problem are studied. The obtained solution indicates that
there are initial and boundary layers and the thickness of the
boundary layer is less than the thickness of the initial layer. 相似文献
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Asymptotic solution for a perturbed mechanism of western boundary undercurrents in the Pacific 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper consider a class of perturbed mechanism for the western
boundary undercurrents in the Pacific. The model of generalized
governing equations is studied. Using the perturbation method, it
constructs the asymptotic solution of the model. And the accuracy of
asymptotic solution is proved by the theory of differential
inequalities. Thus the uniformly valid asymptotic expansions of the
solution are obtained. 相似文献
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A class of combustion problem with shock layers is considered.A modified perturbation method is presented.Using this simple and valid technique,we construct the boundary and the shock layers solution to the problem,and the asymptotic behavior of the solution is discussed.The modifying perturbation method is shown to be a valid method. 相似文献
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