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21.
基于减小列车高速运行时所产生的微气压波,介绍了日本新开发的几种车头形状. 相似文献
22.
The objective of this article is to give an overview about the stochastic inverse method and its application to an ill-posed inverse problem in marine hydrodynamics. In stochastic inversion, it is possible to take into account inherent measurement and system uncertainties in the solution of an inverse problem in a very simple manner. The stochastic inverse method transforms the original inverse problem into the problem of a probabilistic question. Thus, the solution to an inverse problem is described by a distribution of the unknown parameters. These are some main differences with the deterministic inverse method. Stochastic inversion also provides lots of advantages over deterministic inverse methods such as quantitative parameter estimates, determination of confidence intervals, treatments of arbitrary forward maps, error estimates, or parameter estimates given noisy measurement data. In this work, the robust solution procedure from the perspective of the stochastic inverse method is discussed with two different ill-posed inverse problems in marine hydrodynamics. 相似文献
23.
A complete theory to obtain semianalytical solutions of the wave drift damping for a circular cylinder freely oscillating
in waves is developed. The wave drift damping can be significantly increased by heave and pitch motions. Effects of the draft
of the cylinder and effects of the water depth are shown. The effective evaluation of the free-surface integral and the corner
problem are also discussed, and the computed results of the far and near field formulations are compared. These semianalytical
solutions may prove to be important in providing validation of results obtained by numerical techniques such as the higher-order
boundary element method. 相似文献
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25.
Using locally given vertical velocity data around a wing, an inverse formulation is presented to solve a lifting problem.
The inverse problem is expressed by a Fredholm integral equation of the first kind. In this paper, the kernel of the integral
equation gives a Hilbert–Schmidt integral operator, and therefore the occurrence of ill-posedness in the sense of stability
cannot be avoided in a normal topology. This difficulty is solved by using the regularization method for ill-posed problems.
A composition mapping is introduced so that local velocity data can be available for this inverse problem. In this paper,
the ill-posed inverse problem of a wing is studied using the Landweber–Friedman's regularization method within the framework
of linear potential theory. A numerical example demonstrates that only with locally given velocity data is the regularization
method accurate and suitable for the present physical problem of an inverse mathematical formulation. Therefore, the lifting
problem can be solved by using a locally given fluid velocity instead of a wing geometry.
Received: April 13, 2000 / Accepted: April 20, 2000 相似文献