Numerical simulation for 2D multi-connected domain flows in a body-fitted curvilinear coordinate system

Author(s):  
Wei Wenli ◽  
Rong Guiwen
2014 ◽  
Vol 684 ◽  
pp. 145-153 ◽  
Author(s):  
Ji Lin He ◽  
Yun Rong Ma ◽  
Dong Li ◽  
Yao Tan ◽  
Lei Xu

The evolutions of physical properties of composites during the curing process of the carbon fibre reinforced resin composite, such as density, modulus, coefficient of thermal expansion, specific heat capacity and thermal conductivity, were analyzed and those evolutions were introduced into the numerical simulation. The new approach to construct the curvilinear coordinate system by streamline equation of steady flow was proposed with the complex curved structure composite as the study object. By using the finite-element method and building the curvilinear coordinate system, the distribution of internal temperature, degree of cure, internal stresses and evolutions of physical properties during the curing process of the composite skin plate of a light aircraft wing were calculated. The deformation of the skin plate caused by the uneven distributions of temperature field and cure degree field, anisotropic thermal expansion coefficients and volumetric shrinkage of resin were calculated in the same model. From the numerical simulation results, it can be concluded that the curing process will be more reasonable and more accurate when the evolutions of physical properties of composites are adopted and the curvilinear coordinate system constructed by streamline equation of steady flow is fully applicable to finite element analysis of composite curved structure.


1989 ◽  
Vol 111 (4) ◽  
pp. 414-419 ◽  
Author(s):  
T. Solberg ◽  
K. J. Eidsvik

A model for two-dimensional flows over a cylinder at a plane boundary is developed. The model, based upon a (k-ε) turbulence closure, is formulated in a curvilinear coordinate system based upon frictionless flow. A length scale modification in areas of adverse pressure gradient and recirculating flow appears to be more realistic than the standard (k-ε) model. The main features of the predicted flow do not depend critically upon the details of the grid or model, which means that a well defined solution is obtained. The solution appears to be reasonable and validated to the extent that the data permits.


2019 ◽  
Vol 492 (3) ◽  
pp. 4546-4552
Author(s):  
Dmitrii E Vavilov

ABSTRACT This paper presents a robust linear method for impact probability estimation of near-Earth asteroids with the Earth. This method is a significantly modified and improved method, which uses a special curvilinear coordinate system associated with the nominal orbit of an asteroid. One of the coordinates of this system is the mean anomaly in the osculating orbit of an asteroid. A normal distribution of errors of coordinates and velocities of this system is assumed. Because of the usage of the curvilinear coordinate system, the fact that the confidence region is curved and stretched mainly along the nominal asteroid orbit is taken into account. On the main axis of the curvilinear confidence ellipsoid the virtual asteroid, which is the closest to the Earth, is found. The part of the curvilinear confidence ellipsoid, around the found virtual asteroid, is obtained and mapped on to its target plane. The impact probability is calculated as the probability of the asteroid being in the region of the found virtual asteroid multiplied by the probability of a collision of the found virtual asteroid with the Earth. This approach is shown to give more accurate and trustworthy results than the target plane method.


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