4 research outputs found
Comparison of the finite volume and discontinuous Galerkin schemes for the double vortex pairing problem using the SU2 software suite
A numerical investigation of finite volume (FV) and discontinuous Galerkin (DG) finite element methods in the framework of the SU2 software is presented. The accuracy of different numerical variants is assessed with reference to the low Mach double vortex pairing flow problem, which has recently been proposed as a benchmark for studying the properties of structured and unstructured grid based methods with respect to turbulent-like vortices. The present study reveals that low-Mach corrections significantly improve the accuracy of second- and third-order, unstructured grid based schemes, at flow speeds in the incompressible limit. Furthermore, the 3rd-order DG method produces results similar to 11th-order accurate FV volume schemes
A parallel, implicit, multi-dimensional upwind, residual distribution method for the Navier-Stokes equations on unstructured grids
A multi-dimensional cell-vertex upwind discretization technique for the Navier-Strokes equations on unstructured grids is presented. The grids are composed of linear triangles in two and linear tetrahedra in three space dimensions. The nonlinear upwind schemes for the inviscid part can be viewed as a multi-dimensional generalization of the Roe-scheme, but also as a special class of Petrov-Galerkin schemes. They share with these schemes a compact Galerkin stencil, and are in addition monotonic by construction. The Petrov-Galerkin interpretation of the discretization technique allows a straightforward extension to the Navier-Strokes equations. For linear elements this boils down to a Galerkin discretization for the viscous terms. Compared to standard finite-volume methods on these grids, the method shows an increased accuracy, which becomes comparable with structured grid algorithms. The spatially discretized set of equations is integrated in time using the Backward Euler time integration method. The full Jacobian matrix is computed, either numerically by finite differences or approximated analytically, and stored. The resulting set of linear equations is solved by a Block MILU(0) preconditioned Krylov subspace method. For this purpose the Aztec library of SANDIA National Laboratories is used, which also takes care of the parallelization process and completely hides the details for the user. Results are presented for a two-dimensional turbulent shock wave boundary layer interaction in a nozzle and the turbulent flow over an ogive cylinder. All computations have been performed on the Cray T3E of the Technical University of Delft.info:eu-repo/semantics/publishe
The association between WNT10A variants and dental development in patients with isolated oligodontia
In this study we aimed to determine the effect of WNT10A variants on dental development in patients with oligodontia. Forty-three (25 boys and 18 girls) individuals were eligible for this study. Stage of development for each present tooth was assessed using the Demirjian method. In case no corresponding tooth was present, regression equations were applied for dental age to be calculated. The ratio between length of root and length of crown was ascertained for each present tooth in all quadrants. All patients were physically examined by a clinical geneticist and DNA analysis of the WNT10A gene was performed. Linear regression models were applied to analyze the association between WNT10A variants and dental age. The same analysis was applied to study the association between WNT10A variants and root elongation for each present tooth. One ordinal regression model was applied to analyze the association between WNT10A variants and development of present maxillary and mandibular teeth. Thirty-six (84%) patients were detected with WNT10A variants of which six patients displayed evident ectodermal features. Dental age was 1.50 (95% confidence interval (CI): -2.59, -0.42) to 1.96 (95% CI: -3.76, -0.17) years lower in patients with WNT10A variants compared with patients without variants. The development of maxillary canine, maxillary second molar and mandibular second molar was statistically significantly delayed in patients with WNT10A variants compared with patients without variants. The impact of WNT10A variants on dental development increases with presence of the nonsense c.(321C>A p.(C107*)) variant and the number of missing teeth