Equilibrium shapes of ferrofluid under different forces using continuum shape sensitivity analysis and level set method

2010 ◽  
Vol 107 (9) ◽  
pp. 09B519 ◽  
Author(s):  
Young Sun Kim ◽  
Il Han Park
2006 ◽  
Vol 16 (08) ◽  
pp. 1347-1373 ◽  
Author(s):  
GUILLAUME BAL ◽  
KUI REN

We consider the reconstruction of singular surfaces from the over-determined boundary conditions of an elliptic problem. The problem arises in optical and impedance tomography, where void-like structure or cracks may be modeled as diffusion processes supported on co-dimension one surfaces. The reconstruction of such surfaces is obtained theoretically and numerically by combining a shape sensitivity analysis with a level set method. The shape sensitivity analysis is used to define a velocity field, which allows us to update the surface while decreasing a given cost function, which quantifies the error between the prediction of the forward model and the measured data. The velocity field depends on the geometry of the surface and the tangential diffusion process supported on it. The latter process is assumed to be known in this paper. The level set method is next applied to evolve the surface in the direction of the velocity field. Numerical simulations show how the surface may be reconstructed from noisy estimates of the full, or local, Neumann-to-Dirichlet map.


2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Benliang Zhu ◽  
Xianmin Zhang ◽  
Sergej Fatikow

This paper presents an optimization method for solving level set-based topology optimization problems. A predictor–corrector scheme for constructing the velocity field is developed. In this method, after the velocity fields in the first two iterations are calculated using the shape sensitivity analysis, the subsequent velocity fields are constructed based on those obtained from the first two iterations. To ensure stability, the velocity field is renewed based on the shape sensitivity analysis after a certain number of iterations. The validity of the proposed method is tested on the mean compliance minimization problem and the compliant mechanisms synthesis problem. This method is quantitatively compared with other methods, such as the standard level set method, the solid isotropic microstructure with penalization (SIMP) method, and the discrete level set method.


2012 ◽  
Vol 182-183 ◽  
pp. 1668-1672
Author(s):  
Xian Bao Duan ◽  
Fu Cai Qian ◽  
Xin Qiang Qin

This paper presents a general algorithm for topological optimization of the incompressible Navier-Stokes fluid flow based on a level set method. This is a direct extension of our previous work on Stokes flow of such problems. First we obtain the shape sensitivity analysis using the material derivative concept and adjoint variable technique, and then we couple the shape sensitivity analysis result into the level set function as the advection velocity. Since the level set method is implemented in an Euleran framework, the computational cost of the proposed algorithm is moderate. A Benchmark example is provided to illustrate the efficiency and validity of this method.


2018 ◽  
Vol 7 (3.34) ◽  
pp. 273
Author(s):  
Young Sun Kim ◽  
Dong Yoon Lee

Level set methods(LSM) are conceptual methods for using level sets as tools for numerical analysis of surfaces and geometries. The advantage of the level set model is that you can perform numerical calculations involving curves and surfaces in a fixed grid without parameterizing these objects. In recent years, it has been applied to structural design optimization of mechanical engineering, and it has been actively studied as a new design technique overcoming the problems of existing shape sensitivity analysis method and phase optimization method. You can also use the level setting method to easily follow how the topology changes. In this study, we show the application of the level set method to the optimal design using sensitivity analysis. This paper presents applications of dielectric electrode design, moving objects and particle dynamics in magnetic field systems.  


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