scholarly journals WaveRange: wavelet-based data compression for three-dimensional numerical simulations on regular grids

2022 ◽  
Author(s):  
Dmitry Kolomenskiy ◽  
Ryo Onishi ◽  
Hitoshi Uehara
Keyword(s):  
Numerical Simulations ◽  
Wavelet Decomposition ◽  
Three Dimensional ◽  
Global Scale ◽  
Software Framework ◽  
Simulation Data ◽  
Numerical Tests ◽  
Point Data ◽  
Dimensional Simulation ◽  
The Impact

Abstract A wavelet-based method for compression of three-dimensional simulation data is presented and its software framework is described. It uses wavelet decomposition and subsequent range coding with quantization suitable for floating-point data. The effectiveness of this method is demonstrated by applying it to example numerical tests, ranging from idealized configurations to realistic global-scale simulations. The novelty of this study is in its focus on assessing the impact of compression on post-processing and restart of numerical simulations. Graphical abstract

Vortex rings impinging on walls: axisymmetric and three-dimensional simulations

1993 ◽  
Vol 256 ◽  
pp. 615-646 ◽  
Author(s):  
Paolo Orlandi ◽  
Roberto Verzicco
Keyword(s):  
Numerical Simulations ◽  
Strain Tensor ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Vortex Rings ◽  
Compression Phase ◽  
Vortex Pairing ◽  
The Impact ◽  
Good Agreement ◽  
Three Dimensional Simulations

Accurate numerical simulations of vortex rings impinging on flat boundaries revealed the same features observed in experiments. The results for the impact with a free-slip wall compared very well with previous numerical simulations that used spectral methods, and were also in qualitative agreement with experiments. The present simulation is mainly devoted to studying the more realistic case of rings interacting with a no-slip wall, experimentally studied by Walker et al. (1987). All the Reynolds numbers studied showed a very good agreement between experiments and simulations, and, at Rev > 1000 the ejection of a new ring from the wall was seen. Axisymmetric simulations demonstrated that vortex pairing is the physical mechanism producing the ejection of the new ring. Three-dimensional simulations were also performed to investigate the effects of azimuthal instabilities. These simulations have confirmed that high-wavenumber instabilities originate in the compression phase of the secondary ring within the primary one. The large instability of the secondary ring has been explained by analysis of the rate-of-strain tensor and vorticity alignment. The differences between passive scalars and the vorticity field have been also investigated.

Impact of Cavity on Sunroof Buffeting: A Two Dimensional CFD Study

2004 ◽  
Author(s):  
Chang-Fa An ◽  
Seyed Mehdi Alaie ◽  
Michael S. Scislowicz
Keyword(s):  
Fluid Dynamics ◽  
Wind Tunnel ◽  
Three Dimensional ◽  
Leading Edge ◽  
Two Dimensional ◽  
Deep Insight ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
The Impact ◽  
Insight Into

Driven by fluid dynamics principles, the concept for buffeting reduction, a cavity installed at the leading edge of the sunroof opening, is analyzed. The cavity provides a room to hold the vortex, shed from upstream, and prevents the vortex from escaping and from directly intruding into the cabin. The concept has been verified by means of a two dimensional simulation for a production SUV using the CFD software — FLUENT. The simulation results show that the impact of the cavity is crucial to reduce buffeting. It is shown that the buffeting level may be reduced by 3 dB by adding a cavity to the sunroof configuration. Therefore, the cavity could be considered as a means of buffeting reduction, in addition to the three currently-known concepts: wind deflector, sunroof glass comfort position and cabin venting. Thorough understanding of the buffeting mechanism helps explain why and how the cavity works to reduce buffeting. Investigation of the buffeting-related physics provides a deep insight into the flow nature and, therefore, a useful hint to geometry modification for buffeting reduction. The buffeting level may be further reduced by about 4 dB or more by cutting the corners of the sunroof opening into smooth ramps, guided by ideas coming from careful examining the physics of flow. More work including three dimensional simulation and wind tunnel experiment should follow in order to develop more confidence in the functionality of the cavity to hopefully promote this idea to the level that it can be utilized in a feasible way to address sunroof buffeting.

Rogue Wave Impact on a Semi-Submersible Offshore Platform

2008 ◽  
Author(s):  
Murray Rudman ◽  
Paul Cleary ◽  
Justin Leontini ◽  
Matthew Sinnott ◽  
Mahesh Prakash
Keyword(s):  
Rogue Wave ◽  
Three Dimensional ◽  
Breaking Waves ◽  
Attractive Alternative ◽  
Wave Impact ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dimensional Simulation ◽  
The Impact ◽  
Structural Motion

Full three-dimensional simulation of the impact of a rogue wave on a semi-submersible platform is undertaken using the Smoothed Particle Hydrodynamics (SPH) technique. Two different mooring configurations are considered: A Tension Leg Platform (TLP) system and a Taut Spread Mooring (TSM) system. It is seen that for a wave impact normal to the platform side, the heave and surge responses of the platform are significantly different for the two mooring systems. The TLP system undergoes large surge but comparatively smaller heave motions than the TSM system. The degree of pitch is very similar. The total tension in the mooring cables is approximately four times higher in the TSM system and exceeds the strength of the cables used in the simulation. SPH is seen to be an attractive alternative to standard methods for simulating the coupled interaction of highly non-linear breaking waves and structural motion.

scholarly journals Global-scale brittle plastic rheology at the cometesimals merging of comet 67P/Churyumov–Gerasimenko

2020 ◽  
Vol 117 (19) ◽  
pp. 10181-10187
Author(s):  
Marco Franceschi ◽  
Luca Penasa ◽  
Matteo Massironi ◽  
Giampiero Naletto ◽  
Sabrina Ferrari ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Global Scale ◽  
Refractory Materials ◽  
High Porosity ◽  
A Minor ◽  
The Impact ◽  
Comet 67P ◽  
Dextral Strike Slip ◽  
Minor Extent

Observations of comet nuclei indicate that the main constituent is a mix of ice and refractory materials characterized by high porosity (70–75%) and low bulk strength (10−4–10−6 MPa); however, the nature and physical properties of these materials remain largely unknown. By combining surface inspection of comet 67P/Churyumov–Gerasimenko and three-dimensional (3D) modeling of the independent concentric sets of layers that make up the structure of its two lobes, we provide clues about the large-scale rheological behavior of the nucleus and the kinematics of the impact that originated it. Large folds in the layered structure indicate that the merging of the two cometesimals involved reciprocal motion with dextral strike–slip kinematics that bent the layers in the contact area without obliterating them. Widespread long cracks and the evidence of relevant mass loss in absence of large density variations within the comet’s body testify that large-scale deformation occurred in a brittle-plastic regime and was accommodated through folding and fracturing. Comparison of refined 3D geologic models of the lobes with triaxial ellipsoids that suitably represent the overall layers arrangement reveals characteristics that are consistent with an impact between two roughly ellipsoidal cometesimals that produced large-scale axial compression and transversal elongation. The observed features imply global transfer of impact-related shortening into transversal strain. These elements delineate a model for the global rheology of cometesimals that could be possible evoking a prominent bonding action of ice and, to a minor extent, organics.

scholarly journals Assessing the Impact of the Tropopause on Mountain Waves and Orographic Precipitation Using Linear Theory and Numerical Simulations

2015 ◽  
Vol 72 (2) ◽  
pp. 803-820 ◽  
Author(s):  
Nicholas Siler ◽  
Dale Durran
Keyword(s):  
Numerical Simulations ◽  
Linear Theory ◽  
Three Dimensional ◽  
Orographic Precipitation ◽  
Two Dimensional ◽  
Tropopause Height ◽  
Atmospheric Conditions ◽  
Mountain Waves ◽  
Wave Induced ◽  
The Impact

Abstract The partial reflection of mountain waves at the tropopause has been studied extensively for its contribution to downslope windstorms, but its impact on orographic precipitation has not been addressed. Here linear theory and numerical simulations are used to investigate how the tropopause affects the vertical structure of mountain waves and, in turn, orographic precipitation. Relative to the no-tropopause case, wave-induced ascent above the windward slope of a two-dimensional ridge is found to be enhanced or diminished depending on the ratio of the tropopause height to the vertical wavelength of the mountain waves—defined here as the “nondimensional tropopause height” . In idealized simulations of flow over both two-dimensional and three-dimensional ridges, variations in are found to modulate the precipitation rate by roughly a factor of 2 under typical atmospheric conditions. The sensitivity of precipitation to is related primarily to the depth of windward ascent but also to the location and strength of leeside descent, with significant impacts on the distribution of precipitation across the range (i.e., the rain-shadow effect). Using a modified version of Smith and Barstad’s orographic precipitation model, variations in are found to produce significant rain-shadow variability in the Washington Cascades, perhaps explaining some of the variability in rain-shadow strength observed among Cascade storms.

The Dynamic Simulation Study of WN Gear Pair after Coupling Tribology

2014 ◽  
Vol 577 ◽  
pp. 214-217
Author(s):  
Yu Guang Li ◽  
Guo Qing Zhang
Keyword(s):  
Dynamic Simulation ◽  
Three Dimensional ◽  
Dynamic Contact ◽  
Axial Vibration ◽  
Dimensional Model ◽  
Analysis Model ◽  
Ansys Software ◽  
Three Dimensional Model ◽  
Dimensional Simulation ◽  
The Impact

Based on WN gear characteristics and considering system error, a multi-degree-freedom (Tangential-Radial-Axial) dynamics analysis model after coupling friction was established. In this article, we established the three-dimensional solid model by using PROE and then imported WN gear’ three-dimensional model into Ansys software through the data interface of Ansys software and PROE software and conducted a three-dimensional simulation anasys of the impact of dynamic contact. By applying load, the stress analysis of WN gear was conducted and the WN gear’s the effective stress clouds was gotten. Meanwhile, basing on ANSYS / LS-DYNA, it established the rigid-flexible body of gear dynamic contact model and analyzed the dynamic simulation anasys of WN gear. The results demonstrated that the tangential and axial vibration of double arc gear was significantly greater than the radial vibration.

Aerothermal and aerodynamic performance of turbine blade squealer tip under the influence of guide vane passing wake

2020 ◽  
pp. 095765092096573
Author(s):  
Bo Zhang ◽  
Xiaoqing Qiang
Keyword(s):  
Turbine Blade ◽  
Guide Vane ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Computational Domain ◽  
Pressure Loss Coefficient ◽  
Dimensional Simulation ◽  
Unsteady Characteristics ◽  
Annular Cascade ◽  
The Impact

In this paper, the performance of the turbine blade squealer tip has been studied detailed aimed to highlight the impact of the upstream guide vane passing wake. The first stage of GE-E3 high-pressure turbine has been employed to perform the three-dimensional simulation and the computational domain has been scaled based on the domain scaling method. Boundary conditions are consistent with operating conditions of the annular cascade testing. Circumferential averaged and realistic non-uniform interface conditions have been used to obtain steady and unsteady characteristics respectively. The validation of the turbulent model and mesh independent test has been conducted detailed in previous work. Three squealer tips, including two widths and heights, have been designed and investigated to understand its influence. Results show that the aerothermal performance of the squealer tip is remarkably influenced by the upstream passing wake. Although steady and time-averaged results have a good agreement, the variation of instantaneous heat transfer coefficient (HTC) would be over 30%, especially on the Cavity Floor region. Changing the geometry of the squealer also has different impacts on both steady and unsteady performance. The unsteady aerodynamic has relatively small fluctuation within 10%, and the distribution of steady and time-averaged leakage flow as well as total pressure loss coefficient still have a satisfactory agreement.

scholarly journals Transient dynamic finite element simulation for prediction of surface integrity induced by waterjet peening

2019 ◽  
Vol 234 (1) ◽  
pp. 105-119
Author(s):  
Rihem Amri ◽  
Adnen Laamouri ◽  
Sondes Manchoul ◽  
Raouf Fathallah
Keyword(s):  
Finite Element ◽  
Surface Properties ◽  
Three Dimensional ◽  
Element Model ◽  
Transient Dynamic ◽  
Dynamic Finite Element ◽  
Impact Theory ◽  
Experimental Surface ◽  
Dimensional Simulation ◽  
The Impact

This paper aims to develop and validate the transient dynamic finite element three-dimensional simulation of a waterjet peening process to predict surface properties (residual stresses, plastic strains, surface roughness, and superficial damage). The finite-element model considers an impingement of multisets of droplets, which strike the treated surface by impact pressures over the corresponding contact regions at high velocities. The impact pressures and their durations are modelled by using the liquid impact theory combined with an impact velocity law depending on the main parameters of the process. The behavior law of the material is an elastoviscoplastic law coupled to the Johnson–Cook damage criterion. The effectiveness of this simulation is discussed in two cases: (i) a linear mono-set of droplets and (ii) multisets of droplets using the experimental results of a waterjet-peened Al7075-T6 aluminum alloy. The predictive results of surface properties obtained by simulation with multi-sets of droplets appear more realistic than those obtained by simulation with a single set of droplets and more close to the experimental surface properties.

scholarly journals Air entrapment and bubble formation during droplet impact onto a single cubic pillar

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weibo Ren ◽  
Patrick Foltyn ◽  
Anne Geppert ◽  
Bernhard Weigand
Keyword(s):  
Numerical Simulations ◽  
Morphological Changes ◽  
Bubble Formation ◽  
Three Dimensional ◽  
Air Entrapment ◽  
Droplet Dynamics ◽  
Entrapped Air ◽  
The Impact ◽  
Insight Into ◽  
Vertical Impact

AbstractWe study the vertical impact of a droplet onto a cubic pillar of comparable size placed on a flat surface, by means of numerical simulations and experiments. Strikingly, during the impact a large volume of air is trapped around the pillar side faces. Impingement upon different positions of the pillar top surface strongly influences the size and the position of the entrapped air. By comparing the droplet morphological changes during the impact from both computations and experiments, we show that the direct numerical simulations, based on the Volume of Fluid method, provide additional and new insight into the droplet dynamics. We elucidate, with the computational results, the three-dimensional air entrapment process as well as the evolution of the entrapped air into bubbles.

scholarly journals CALIPSO-Derived Three-Dimensional Structure of Aerosol over the Atlantic Basin and Adjacent Continents

2012 ◽  
Vol 25 (19) ◽  
pp. 6862-6879 ◽  
Author(s):  
Aaron M. Adams ◽  
Joseph M. Prospero ◽  
Chidong Zhang
Keyword(s):  
South African ◽  
Three Dimensional ◽  
Global Scale ◽  
Dimensional Structure ◽  
Vertical Profiles ◽  
Transport Pathways ◽  
African Dust ◽  
Microphysical Processes ◽  
The Impact ◽  
Broad Region

Abstract Accurate modeling of the impact of aerosols on climate requires a detailed understanding of the vertical distribution of aerosols. The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) provides continuous high-resolution vertical profiles of aerosol properties on a near-global scale. Here the CALIPSO Vertical Feature Mask is used to document the three-dimensional (3D) frequency-of-occurrence distribution of aerosols over a broad region of the Atlantic Ocean, Africa, Europe, and the Americas. The 3D distributions illustrate the seasonal cycle in the zonal and meridional variability of the vertical profiles of mineral dust, biomass-burning smoke, polluted dust (external mixture of dust and smoke), and polluted continental aerosol, and also of their emissions sources and transport pathways. Four aerosol domains stand out in the product: dust over North Africa and the Middle East and smoke over southern Africa and South America. The transport pathways of African dust and smoke over the Atlantic are evident. The intertropical convergence zone (ITCZ) plays a clear role in limiting the southward transport of North African dust and northward transport of South African smoke. Dust and smoke are mixed in the ITCZ and consequently the highest probability of polluted dust is found there, even though the probabilities of dust and smoke in this region are relatively low. The mixing of dust and pollution has significant implications for cloud microphysical processes over a broad region of the Atlantic.

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