scholarly journals Stable high-order cubature formulas for experimental data

2021 ◽  
Vol 447 ◽  
pp. 110693
Author(s):  
Jan Glaubitz
Keyword(s):  
Experimental Data ◽  
High Order ◽  
Cubature Formulas

scholarly journals Numerical Simulation of Breaking Wave Loading on Standing Circular Cylinders with Different Transverse Inclined Angles

2020 ◽  
Vol 10 (4) ◽  
pp. 1347
Author(s):  
Sen Qu ◽  
Shengnan Liu ◽  
Muk Chen Ong ◽  
Shuzheng Sun ◽  
Huilong Ren
Keyword(s):  
Experimental Data ◽  
Vertical Cylinder ◽  
Wave Force ◽  
High Order ◽  
Numerical Results ◽  
Circular Cylinders ◽  
Wave Forces ◽  
Breaking Wave ◽  
Time Step ◽  
Inclined Angle

The purpose of this paper is to numerically simulate the breaking wave past a standing cylinder with different transverse inclined angles. The numerical simulations are carried out by solving the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations with the k − ω S S T turbulence model. The air–water interface is captured using the Volume of Fluid (VOF) method. The convergence studies on the grid and time-step are performed by examining the total horizontal breaking wave forces on the vertical cylinder. The present numerical results have been validated with the published experimental data. A good agreement is obtained between the present numerical results and the experimental data in terms of the surface elevation and the horizontal breaking wave force. Moreover, the total horizontal breaking wave force is decomposed into low-order and high-order wave forces through Fast Fourier Transform (FFT). It is observed that the free surface elevations in front of the cylinder and the normalized high-order wave force have a minimum value when the transverse inclined angle of the cylinder is 45°. The secondary load causing the higher-harmonic ringing motion of structures is not observed when the cylinder is placed with the transverse inclined angles of 30° and 45°.

Investigation of Compressor Tip Clearance Flow Based on the Discontinuous Galerkin Methods

2013 ◽  
Author(s):  
Xiaodong Ren ◽  
Chunwei Gu
Keyword(s):  
Experimental Data ◽  
High Order ◽  
Tip Clearance ◽  
High Order Accuracy ◽  
Numerical Dissipation ◽  
Order Accuracy ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Clearance Flow ◽  
Slope Limiter

The tip clearance flow has a significant influence on the compressor performance and stability. CFD, which is a current tool, has been widely used to investigate the flow by many researchers. In this paper, an unstructured-grid code based on a RKDG method was developed with an improved vertex-based slope limiter to ensure the nonlinear stability. The limiter tests show that the improved limiter has less numerical dissipation and it can keep the high-order accuracy. The performance for NASA Rotor 37 was simulated to validate the RKDG code. The results are compared with the experimental data and the ones computed by NUMECA FINE™/Turbo. It is shown that the results computed by the RKDG code are in better agreement with the experimental data, which implies that the high-order accuracy method is very important for improving the CFD reliability. Finally, the tip clearance flow of the compressor was investigated using the RKDG code. It is found that the tip leakage jet flow could be separated into two parts and they go downstream separately without mixing.

Theoretical investigations of 63Cu2+ orbital Knight shifts for YBa2Cu4O8

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542007 ◽  
Author(s):  
Min-Quan Kuang ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Xian-Fen Hu
Keyword(s):  
Experimental Data ◽  
Experimental Verification ◽  
High Order ◽  
Order Perturbation ◽  
Theoretical Investigations ◽  
Calculation Results ◽  
Knight Shifts ◽  
Good Agreement

The temperature-independent orbital Knight shifts for the orthorhombic [Formula: see text] site in [Formula: see text] (Y124) are investigated by utilizing the high order perturbation formulae of these parameters for a [Formula: see text] ion situated into orthorhombically elongated octahedra. The calculation results are in good agreement with the experimental data. The moderate quasi-axial anisotropies of the Knight shifts are ascribed to the elongation distortion of the four-fold coordinated Cu[Formula: see text] site. The [Formula: see text] factors are also theoretically calculated in a uniform way for further experimental verification.

scholarly journals Fast computation of elastic and hydrodynamic potentials using approximate approximations

2020 ◽  
Vol 10 (4) ◽  
Author(s):  
Flavia Lanzara ◽  
Vladimir Maz’ya ◽  
Gunther Schmidt
Keyword(s):  
Integral Operator ◽  
Tensor Product ◽  
Numerical Experiments ◽  
Approximation Order ◽  
High Order ◽  
Fast Computation ◽  
Product Representation ◽  
Cubature Formulas ◽  
Separated Representation ◽  
Tensor Product Representation

AbstractWe propose fast cubature formulas for the elastic and hydrodynamic potentials based on the approximate approximation of the densities with Gaussian and related functions. For densities with separated representation, we derive a tensor product representation of the integral operator which admits efficient cubature procedures. We obtain high order approximations up to a small saturation error, which is negligible in computations. Results of numerical experiments which show approximation order $$\mathscr {O}(h^{2M})$$ O ( h 2 M ) , $$M=1,2,3,4$$ M = 1 , 2 , 3 , 4 , are provided.

Large Eddy Simulation of Gasoline Sprays in a Lagrangian-Eulerian Framework Using the High-Order Spectral Element Method

2021 ◽  
Author(s):  
Juan D. Colmenares F. ◽  
Muhsin M. Ameen ◽  
Saumil S. Patel
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Gas Flow ◽  
Spectral Element Method ◽  
Cone Angle ◽  
Spectral Element ◽  
High Order ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Element Method

Abstract Predicting the spray evolution using simulations requires accurate modeling of the turbulent gas-phase flow field. In this study, the high-order spectral-element method (SEM), implemented in the code Nek5000, was used to provide highly-resolved solutions to the turbulent flow field. Spray modeling capabilities were implemented into the Nek5000 code. The spray is modeled in a Lagrangian-Eulerian (LE) framework, where the liquid is represented by discrete parcels of droplets. The method for coupling liquid and gas in the context of SEM is described, which allows for very fine meshes to be used without affecting the stability of the solution. Large-eddy simulations (LES) of the eight-hole ECN Spray G gasoline injector were conducted. Numerical results are compared against experimental data for liquid penetration, droplet size and gas velocity. The morphology of the multi-plume spray is compared against experimental data. The effect of different spray injection inputs is analyzed. It was found that using a plume direction of 33° and an injection cone angle of 30° produced the best results overall. This work shows the applicability of SEM for spray modeling applications, where use of a high-order flow solver can help us understand the multi-plume spray aerodynamics and how it leads to plume collapse under certain conditions. Results also highlight the need for tuning spray input parameters in the LE framework, even when high-fidelity gas flow solutions are possible.

scholarly journals HIGH ORDER QED CORRECTIONS IN POSITRONIUM PHYSICS

2004 ◽  
Vol 19 (23) ◽  
pp. 3897-3903 ◽  
Author(s):  
ALEXANDER A. PENIN
Keyword(s):  
Experimental Data ◽  
Hyperfine Splitting ◽  
High Order ◽  
Recent Experimental Data ◽  
Theoretical Predictions ◽  
Perturbative Corrections

High-order perturbative corrections to positronium decays and hyperfine splitting are briefly reviewed. Theoretical predictions are compared to the most recent experimental data. Perspectives of future calculations are discussed.

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