Finite transformation rigid motion mesh morpher; A grid deformation approach

2020 ◽  
Author(s):  
Athanasios G. Liatsikouras ◽  
Gabriel Fougeron ◽  
George S. Eleftheriou ◽  
Guillaume Pierrot
Keyword(s):  
Rigid Motion ◽  
Grid Deformation ◽  
Finite Transformation ◽  
Deformation Approach

A structure-aware axis-aligned grid deformation approach for robust image retargeting

2017 ◽  
Vol 77 (6) ◽  
pp. 7717-7739 ◽  
Author(s):  
Yoonhyung Kim ◽  
Seungjun Jung ◽  
Chanho Jung ◽  
Changick Kim
Keyword(s):  
Image Retargeting ◽  
Grid Deformation ◽  
Robust Image ◽  
Deformation Approach

scholarly journals An Efficient Mesh Generation Method for Fractured Network System Based on Dynamic Grid Deformation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shuli Sun ◽  
Jie Sui ◽  
Bin Chen ◽  
Mingwu Yuan
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Network System ◽  
Computational Domain ◽  
Topological Transformation ◽  
Grid Deformation ◽  
Insertion Algorithm ◽  
Fractured Network ◽  
Deformation Approach

Meshing quality of the discrete model influences the accuracy, convergence, and efficiency of the solution for fractured network system in geological problem. However, modeling and meshing of such a fractured network system are usually tedious and difficult due to geometric complexity of the computational domain induced by existence and extension of fractures. The traditional meshing method to deal with fractures usually involves boundary recovery operation based on topological transformation, which relies on many complicated techniques and skills. This paper presents an alternative and efficient approach for meshing fractured network system. The method firstly presets points on fractures and then performs Delaunay triangulation to obtain preliminary mesh by point-by-point centroid insertion algorithm. Then the fractures are exactly recovered by local correction with revised dynamic grid deformation approach. Smoothing algorithm is finally applied to improve the quality of mesh. The proposed approach is efficient, easy to implement, and applicable to the cases of initial existing fractures and extension of fractures. The method is successfully applied to modeling of two- and three-dimensional discrete fractured network (DFN) system in geological problems to demonstrate its effectiveness and high efficiency.

scholarly journals Development of an Aeroelastic Code Based on an Euler / Navier-Stokes Aerodynamic Solver

1996 ◽  
Author(s):  
Milind A. Bakhle ◽  
Rakesh Srivastava ◽  
George L. Stefko ◽  
J. Mark Janus
Keyword(s):  
Navier Stokes ◽  
Aeroelastic Stability ◽  
Paper Briefly ◽  
Relevant Research ◽  
Unsteady Aerodynamic ◽  
Grid Deformation ◽  
Stage Of Development ◽  
Development And Validation ◽  
Further Development ◽  
Deformation Approach

This paper describes the development of an aeroelastic code (TURBO-AE) based on an Euler / Navier-Stokes unsteady aerodynamic analysis. A brief review of the relevant research in the area of propulsion aeroelasticity is presented. The paper briefly describes the original Euler / Navier-Stokes code (TURBO) and then details the development of the aeroelastic extenstons. The aeroelastic formulation is described. The modeling of the dynamics of the blade using a modal approach is detailed, along with the grid deformation approach used to model the elastic deformation of the blade. The work-per-cycle approach used to evaluate aeroelastic stability is described. Representative results used to verify the code are presented. At the present stage of development, the aeroelastic code is limited to in-phase blade motions. The paper concludes with an evaluation of the development thus far, and some plans for further development and validation of the TURBO-AE code.

scholarly journals Estimating intrafraction tumor motion during fiducial-based liver stereotactic radiotherapy via an iterative closest point (ICP) algorithm

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Wu-zhou Li ◽  
Zhi-wen Liang ◽  
Yi Cao ◽  
Ting-ting Cao ◽  
Hong Quan ◽  
...  
Keyword(s):  
Stereotactic Radiotherapy ◽  
Imaging System ◽  
Liver Tumors ◽  
Three Dimensional ◽  
Rigid Motion ◽  
Iterative Closest Point ◽  
Tumor Motion ◽  
Tracking Accuracy ◽  
Icp Algorithm ◽  
Anterior Posterior

Abstract Background Tumor motion may compromise the accuracy of liver stereotactic radiotherapy. In order to carry out a precise planning, estimating liver tumor motion during radiotherapy has received a lot of attention. Previous approach may have difficult to deal with image data corrupted by noise. The iterative closest point (ICP) algorithm is widely used for estimating the rigid registration of three-dimensional point sets when these data were dense or corrupted. In the light of this, our study estimated the three-dimensional (3D) rigid motion of liver tumors during stereotactic liver radiotherapy using reconstructed 3D coordinates of fiducials based on the ICP algorithm. Methods Four hundred ninety-five pairs of orthogonal kilovoltage (KV) images from the CyberKnife stereo imaging system for 12 patients were used in this study. For each pair of images, the 3D coordinates of fiducial markers inside the liver were calculated via geometric derivations. The 3D coordinates were used to calculate the real-time translational and rotational motion of liver tumors around three axes via an ICP algorithm. The residual error was also investigated both with and without rotational correction. Results The translational shifts of liver tumors in left-right (LR), anterior-posterior (AP),and superior-inferior (SI) directions were 2.92 ± 1.98 mm, 5.54 ± 3.12 mm, and 16.22 ± 5.86 mm, respectively; the rotational angles in left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were 3.95° ± 3.08°, 4.93° ± 2.90°, and 4.09° ± 1.99°, respectively. Rotational correction decreased 3D fiducial displacement from 1.19 ± 0.35 mm to 0.65 ± 0.24 mm (P<0.001). Conclusions The maximum translational movement occurred in the SI direction. Rotational correction decreased fiducial displacements and increased tumor tracking accuracy.

scholarly journals A Korn-type inequality in SBD for functions with small jump sets

2017 ◽  
Vol 27 (13) ◽  
pp. 2461-2484 ◽  
Author(s):  
Manuel Friedrich
Keyword(s):  
Bounded Variation ◽  
Elastic Strain ◽  
Special Functions ◽  
Type Inequality ◽  
Rigid Motion ◽  
Exceptional Set ◽  
Finite Perimeter ◽  
Functions Of Bounded Deformation ◽  
Jump Set

We present a Korn-type inequality in a planar setting for special functions of bounded deformation. We prove that for each function in [Formula: see text] with a sufficiently small jump set the distance of the function and its derivative from an infinitesimal rigid motion can be controlled in terms of the linearized elastic strain outside of a small exceptional set of finite perimeter. Particularly, the result shows that each function in [Formula: see text] has bounded variation away from an arbitrarily small part of the domain.

Time-Accurate Simulation of Longitudinal Flight Mechanics with Control by CFD/RBD Coupling

2012 ◽  
Vol 226-228 ◽  
pp. 788-792 ◽  
Author(s):  
Dong Guo ◽  
Min Xu ◽  
Shi Lu Chen
Keyword(s):  
Computational Study ◽  
Rigid Motion ◽  
Rigid Body Dynamics ◽  
Flight Mechanics ◽  
Control Surface ◽  
Free Flight ◽  
Body Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Coupled Solution ◽  
Surface Deflections

This paper describes a multidisciplinary computational study undertaken to compute the flight trajectories and simultaneously predict the unsteady free flight aerodynamics of aircraft in time domain using an advanced coupled computational fluid dynamics (CFD)/rigid body dynamics (RBD) technique. This incorporation of the flight mechanics equations and controller into the CFD solver loop and the treatment of the mesh, which must move with both the control surface deflections and the rigid motion of the aircraft, are illustrated. This work is a contribution to a wider effort towards the simulation of aeroelastic and flight stability in regions where nonlinear aerodynamics, and hence potentially CFD, can play a key role. Results demonstrating the coupled solution are presented.

scholarly journals A Numerical Study of Separation Performance of Vibrating Flip-Flow Screens for Cohesive Particles

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 631
Author(s):  
Chi Yu ◽  
Runhui Geng ◽  
Xinwen Wang
Keyword(s):  
Surface Energy ◽  
Numerical Study ◽  
Energy Levels ◽  
Great Influence ◽  
Rigid Motion ◽  
Separation Performance ◽  
Gravitational Acceleration ◽  
Screening Process ◽  
Vibration Intensity ◽  
Screen Surface

Vibrating flip-flow screens (VFFS) are widely used to separate high-viscosity and fine materials. The most remarkable characteristic is that the vibration intensity of the screen frame is only 2–3 g (g represents the gravitational acceleration), while the vibration intensity of the screen surface can reach 30–50 g. This effectively solves the problem of the blocking screen aperture in the screening process of moist particles. In this paper, the approximate state of motion of the sieve mat is realized by setting the discrete rigid motion at multiple points on the elastic sieve mat of the VFFS. The effects of surface energy levels between particles separated via screening performance were compared and analyzed. The results show that the flow characteristics of particles have a great influence on the separation performance. For 8 mm particle screening, the particle’s velocity dominates its movement and screening behavior in the range of 0–8 J/m2 surface energy. In the feeding end region (Section 1 and Section 2), with the increase in the surface energy, the particle’s velocity decreases, and the contact time between the particles and the screen surface increases, and so the passage increases. When the surface energy level continues to increase, the particles agglomerate together due to the effect of the cohesive force, and the effect of the particle’s agglomeration is greater than the particle velocity. Due to the agglomeration of particles, the difficulty of particles passing through the screen increases, and the yields of various size fractions in the feeding end decrease to some extent. In the transporting process, the agglomerated particles need to travel a certain distance before depolymerization, and the stronger the adhesive force between particles, the larger the depolymerization distance. Therefore, for the case of higher surface energy, the screening percentage near the discharging end (Section 3 and Section 4) is greater. The above research is helpful to better understand and optimize the screening process of VFFS.

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