Cubic Local Splines on Non-uniform Grid

2015 ◽  
pp. 115-126
Author(s):  
Amir Z. Averbuch ◽  
Pekka Neittaanmäki ◽  
Valery A. Zheludev
Keyword(s):  
Uniform Grid ◽  
Local Splines

Local Splines on Non-uniform Grid

2018 ◽  
pp. 83-113
Author(s):  
Amir Z. Averbuch ◽  
Pekka Neittaanmäki ◽  
Valery A. Zheludev
Keyword(s):  
Uniform Grid ◽  
Local Splines

scholarly journals Cartesian Mesh Generation with Local Refinement for Immersed Boundary Approaches

2021 ◽  
Vol 9 (6) ◽  
pp. 572
Author(s):  
Luca Di Di Angelo ◽  
Francesco Duronio ◽  
Angelo De De Vita ◽  
Andrea Di Di Mascio
Keyword(s):  
Mesh Generation ◽  
Cfd Simulation ◽  
Automatic Generation ◽  
Uniform Grid ◽  
Immersed Boundary ◽  
Adaptive Grids ◽  
Local Refinement ◽  
User Interactions ◽  
Cartesian Mesh ◽  
Time Required

In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Immersed Boundary Approach is proposed, whose key feature is the capability of high Reynolds number simulations by the use of wall function models, bypassing the need for accurate boundary layer discretization. Starting from the discrete manifold model of the object to be analyzed, the proposed model generates Cartesian adaptive grids for a CFD simulation, with minimal user interactions; the most innovative aspect of this approach is that the automatic generation is based on the segmentation of the surfaces enveloping the object to be analyzed. The aim of this paper is to show that this automatic workflow is robust and enables to get quantitative results on geometrically complex configurations such as marine vehicles. To this purpose, the proposed methodology has been applied to the simulation of the flow past a BB2 submarine, discretized by non-uniform grid density. The obtained results are comparable with those obtained by classical body-fitted approaches but with a significant reduction of the time required for the mesh generation.

scholarly journals Heat Transfer Study of the Ferrofluid Flow in a Vertical Annular Cylindrical Duct under the Influence of a Transverse Magnetic Field

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 120
Author(s):  
Panteleimon Bakalis ◽  
Polycarpos Papadopoulos ◽  
Panayiotis Vafeas
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Field Strength ◽  
Circular Cross Section ◽  
Transverse Magnetic ◽  
Uniform Grid ◽  
Volumetric Concentration ◽  
Flow And Heat Transfer ◽  
Axial Pressure Gradient ◽  
Transfer Study

We studied the laminar fully developed ferrofluid flow and heat transfer phenomena of an otherwise magnetic fluid into a vertical annular duct of circular cross-section and uniform temperatures on walls which were subjected to a transverse external magnetic field. A computational algorithm was used, which coupled the continuity, momentum, energy, magnetization and Maxwell’s equations, accompanied by the appropriate conditions, using the continuity–vorticity–pressure (C.V.P.) method and a non-uniform grid. The results were obtained for different values of field strength and particles’ volumetric concentration, wherein the effects of the magnetic field on the ferrofluid flow and the temperature are revealed. It is shown that the axial velocity distribution is highly affected by the field strength and the volumetric concentration, the axial pressure gradient depends almost linearly on the field strength, while the heat transfer significantly increases due to the generated secondary flow.

On lower bounds for the approximation of individual functions by local splines with nonfixed nodes

1999 ◽  
Vol 51 (12) ◽  
pp. 1839-1849
Author(s):  
A. A. Ligun ◽  
A. A. Shumeiko
Keyword(s):  
Lower Bounds ◽  
Local Splines

Finite‐difference calculation of direct‐arrival traveltimes using the eikonal equation

Geophysics ◽  
2002 ◽  
Vol 67 (4) ◽  
pp. 1270-1274 ◽  
Author(s):  
Le‐Wei Mo ◽  
Jerry M. Harris
Keyword(s):  
Finite Difference ◽  
Ray Tracing ◽  
Finite Differences ◽  
Eikonal Equation ◽  
Velocity Model ◽  
Uniform Grid ◽  
Square Grid ◽  
Kirchhoff Migration ◽  
Difference Calculation

Traveltimes of direct arrivals are obtained by solving the eikonal equation using finite differences. A uniform square grid represents both the velocity model and the traveltime table. Wavefront discontinuities across a velocity interface at postcritical incidence and some insights in direct‐arrival ray tracing are incorporated into the traveltime computation so that the procedure is stable at precritical, critical, and postcritical incidence angles. The traveltimes can be used in Kirchhoff migration, tomography, and NMO corrections that require traveltimes of direct arrivals on a uniform grid.

UNICORE as Uniform Grid Environment for Life Sciences

2005 ◽  
pp. 364-373 ◽  
Author(s):  
Krzysztof Benedyczak ◽  
Michał Wroński ◽  
Aleksander Nowiński ◽  
Krzysztof S. Nowiński ◽  
Jarosław Wypychowski ◽  
...  
Keyword(s):  
Life Sciences ◽  
Uniform Grid ◽  
Grid Environment

scholarly journals Calculation of Horseshoe Vortex Flow Without Numerical Mixing

1984 ◽  
Author(s):  
Joan G. Moore ◽  
John Moore
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Companion Paper ◽  
New Method ◽  
Uniform Grid ◽  
Grid Spacing ◽  
Three Dimensional Flow ◽  
Numerical Mixing ◽  
Well Posed

The usefulness of three-dimensional flow calculations has frequently been obscured by the numerical mixing present in the calculation methods. This paper describes a new method of forming the finite difference momentum equations. The new method results in well posed equations which introduce no numerical mixing. It may be used with orthogonal or non-orthogonal grids and with uniform or highly non-uniform grid spacing. The method is demonstrated by comparing it with upwind differencing on the calculation of a simple example. It is then used in an elliptic pressure-correction calculation procedure to calculate a leading edge horseshoe vortex about a Rankine half body. The results compare well with the experimental data presented in a companion paper.

scholarly journals Calibration of a transient transport model to tritium data in streams and simulation of groundwater ages in the western Lake Taupo catchment, New Zealand

2013 ◽  
Vol 17 (3) ◽  
pp. 1217-1227 ◽  
Author(s):  
M. A. Gusyev ◽  
M. Toews ◽  
U. Morgenstern ◽  
M. Stewart ◽  
P. White ◽  
...  
Keyword(s):  
New Zealand ◽  
Transport Model ◽  
Groundwater Age ◽  
Uniform Grid ◽  
Groundwater System ◽  
Small Surface ◽  
Streams And Rivers ◽  
Groundwater Levels ◽  
Transient Transport ◽  
Western Lake

Abstract. Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model of the western Lake Taupo catchment, New Zealand. Tritium has a known pulse-shaped input to groundwater systems due to the bomb tritium in the early 1960s and, with its radioactive half-life of 12.32 yr, allows for the determination of the groundwater age. In the transport model, the tritium input (measured in rainfall) passes through the groundwater system, and the simulated tritium concentrations are matched to the measured tritium concentrations in the river and stream outlets for the Waihaha, Whanganui, Whareroa, Kuratau and Omori catchments from 2000–2007. For the Kuratau River, tritium was also measured between 1960 and 1970, which allowed us to fine-tune the transport model for the simulated bomb-peak tritium concentrations. In order to incorporate small surface water features in detail, an 80 m uniform grid cell size was selected in the steady-state MODFLOW model for the model area of 1072 km2. The groundwater flow model was first calibrated to groundwater levels and stream baseflow observations. Then, the transient tritium transport MT3DMS model was matched to the measured tritium concentrations in streams and rivers, which are the natural discharge of the groundwater system. The tritium concentrations in the rivers and streams correspond to the residence time of the water in the groundwater system (groundwater age) and mixing of water with different age. The transport model output showed a good agreement with the measured tritium values. Finally, the tritium-calibrated MT3DMS model is applied to simulate groundwater ages, which are used to obtain groundwater age distributions with mean residence times (MRTs) in streams and rivers for the five catchments. The effect of regional and local hydrogeology on the simulated groundwater ages is investigated by demonstrating groundwater ages at five model cross-sections to better understand MRTs simulated with tritium-calibrated MT3DMS and lumped parameter models.

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