VNoise Release Note 3.1
Vibroacoustic analysis made feasible and effectiveVNoise 3.1
Full support for multi-core CPUs ensures an impressive 2x or 4x speed gain on dual or quad core architecture. A single desktop PC can now perform analyses once limited to UNIX servers. With 2 or 3 desktop PCs placed on a standard LAN you can perform analyses that before were simply not feasible even using dedicated clusters.
VNoise 3.1
major improvements introduces a direct, full support for modern multi core CPUs, ensuring a 2x or 4x performance gain respectively on dual and quad core processors.
The multi-core support coupled with VNoiseCluster that permits to perform large and huge calculations using 2 or more PC connected by a standard LAN, constitute a powerful and flexible number crunching machine for vibroacoustic applications. You can seamless mix single, dual, or quad core CPUs in a simple LAN to obtain a powerful environment for vibroacoustic analyses of large models that are not feasible using other platforms. Some performance example for some typical applications, are here reported. All the analyses have been conducted using a single PC based on an Intel quad core CPU of the cost of about 2K euro.
Muffler shell noise
An exhaust system with a complex internal structure has been considered. The inlet source is characterized and applied at inlet. External sound radiated both by outlet and by the external skin vibration is evaluated. Coupling with structural modes is considered. The model was about 6000 Nodes and the analysis from 20Hz to 1000Hz with 10Hz step was completed in 2.5 hours.
External radiation from a complex driller
A very complex driller model with imposed surface vibration, and ground presence. The full model was about 12000 nodes . The analysis in the frequency range from 250Hz up to 1500Hz with a 10Hz step required just 18 hours.
High frequency car pass-by Noise
The analysis of a very large model of 22000 nodes for external car pass-by noise required less then 20 minutes for each frequency step.
Engine transfer function
The evaluation of the transfer function at 10 microphones for a 7000 nodes engine model, in the range from 10Hz to 1500Hz with 50Hz step was performed in 3.2 hours.
Random Vibroacoustic analysis of a Solar Array
The full random vibroacoustic analysis of a solar array in the frequency range from 20Hz to 500Hz with a 4Hz step required about 6 hours.
Computational Core
o Frequency response with Direct and Indirect BEM.
o Mixed domain and multi-domain formulations.
o Internal, External and mixed problems. All the formulations (Direct, Indirect, mixed domain and multi domain) can be used contemporaneously for different parts of the same model.
o Fully coupled structural-acoustic analysis through the coupling with modal structural equations.
o Contribution Vectors for fast multi frequency radiation analysis (i.e. engine run up).
o Extremely complete set of boundary conditions, including pressure, velocity, and robin conditions, as well as free edges, radiation conditions, and baffled and un-baffled aperture, for openings simulation.
o Sound absorbing trims with acoustic impedance.
o Complex speed of sound and densities, for modelling bulk reacting materials.
o Different speed of sound and densities for different domains in the same calculation.
o User customizable coupling conditions at interfaces between different domains.
o Impedance and transfer matrix relations for black box modelling of filters and other acoustics elements.
o Modelling of perforated tubes and surfaces.
o Frequency interpolation for multi frequency analysis.
o Half space formulation, planar, and axial symmetries.
o Fully automatic, and extremely robust routine for CHIEF nodes.
o Isoparametric discretization of 1st and 2nd order.
o Monopole, dipole and plane wave sound sources with frequency dependent intensity.
o User customizable sound source by direct import of incident pressure.
o Linear system solved using an iterative solver of the GMRES family that ensure great convergence speeds and stability.
o Direct Solver for small sized problems.
o Automatic use of out of core solver for big problems.
o Multiple load case analysis.
o Random Vibroacoustic analysis with evaluation of PSD auto-cross correlations, and RMS values, of both acoustic and structural quantities. Diffuse field modelling.
User Interface
o PC Based (Windows XP/2000/NT).
o CAD and meshing features for modelling simple geometries.
o Full Interface with FEM/CAE tools including NASTRAN (bulk, f06, MSC op2, punch), ANSYS (rst), FEMAP, NEiNastran, Patran Neutral Files.
o Automatic features for converting FEM meshes into BEM meshes (Free edge and intersection detection, nodes disconnection, normal orientation check, hole closure, volume elements skin detection, check for degenerated elements).
o Batch file for automating multiple operations and analysis.
o Easily programmable TAG based ASCII file format (VNoiseX) for automating import/export operations.
o Advanced import features for managing large FEM results files.
o Fully Automatic Mesh Coarsening based on an edge collapsing technique tailored for acoustic.
o Mesh refinement and improvement tools.
o Modal and velocity data projection with stable and accurate 3D interpolation and integration routines that permit to easily exchange data among different sources and discretizations.
o Simultaneous use of different models and analysis in background. The user can execute a calculation while he is executing pre-post processing operations with other models.
o Complete set of 2D and 3D plots and animations.
o Evaluation of Intensity, SPL, RMS, dBA, dBC, 1/3 octave, and specific functions for Transmission Loss and Insertion Loss.
o Sound Power evaluation from direct Intensity integration, or from ISO procedures.
o Audio Replay capabilities for listening to the computed noise (wave files generation for further processing outside VNoise).
o Microphones arrays (Spherical, annular, planar).
o Structural forces and pressure distributions.
o Complete documentation and tutorials.
o Responsive and highly qualified technical support.
FEMAP/NEiNastran Interface
o Direct link that permits to exchange model and data with FEMAP/NEiNastran.
o Through FEMAP provide VNoise interface to the CAD tools supported by FEMAP (CATIA, Pro/Engineer,
AutoDesk, SolidWorks and Solid Edge).
VNoise Cluster
o Distribute huge calculations across a simple PC network. No configuration needed.
o Impressive increase of computational power at a low software and hardware cost.
o Support for multi-core CPU
FWH Solver
o Sound radiated by aeroacoustic sources such as rotating blades, fans, and turbulence.
o Use the unsteady pressure computed by CFD codes for the evaluation of radiated noise, using an acoustic analogy based on the integration of the full FWH equations.
o Interface with CFD codes (Fluent).
辛苦了，孜孜不倦的推广！
有几个问题想请教一下：
1.该软件具有前处理模块么？
2.能否处理厚壳（体单元模型）与流体的多重耦合问题（流体有限元+结构有限元+边界元）？
3.计算时有没有计算内存限制？
[ 本帖最后由 w89986581 于 2008-2-3 16:15 编辑 ] 看上去似乎还不错。
回复 2楼 的帖子
1.有自己的前处理模块。但是较为简单，和其它的噪声分析软件一样，前处理软件显得相对较弱一些。2.可以处理厚壳与流体的多重耦合问题。
[ 本帖最后由 doris616161 于 2008-2-19 17:59 编辑 ] 谢谢4楼 原帖由 doris616161 于 2008-2-19 17:57 发表 http://www.chinavib.com/forum/images/common/back.gif
1.有自己的前处理模块。但是较为简单，和其它的噪声分析软件一样，前处理软件显得相对较弱一些。
2.可以处理厚壳与流体的多重耦合问题。
该软件可以处理体单元么？都支持什么类型的体单元？
回复 6楼 的帖子
体单元可以转成边界元，在vnoise软件中既可以操作。软件本身具有转换的功能。
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