科學計算視覺化

iHPC Gimmick: Real-Time Air Flow Simulation and Visualization

We combine simulation, visualization and interaction modules to create a 2D/3D supersonic air flow simulation application. Users can change parameters for the simulation, and even interactively change the object in this numerical wind tunnel. It also uses shader programs to create different display modes that can show a variety of data sets, or different visualization effects.

The result is accepted by Computer Graphics Workshop 2013 (CGW 2013).

2D Version

3D Version

Real-time Interactive GPU flow simulation and visualization

Simulation: Dr. Matthew Smith;

Visualilzation: Visualization and Interactive Media Lab at NCHC.

Presented is compressible flow around an arbitrary shape.

In this case, a finite plane – for compressible flow of low mach number. The governing equations are the compressible Navier-Stokes equations for an ideal gas, solved using a Total Variable Diminishing (TVD) transient Finite Volume Method (FVM). The discretized form of these equations are solved in real-time using GPU.

In this case, using CUDA. Since the GPU is essentially a vector computer, the efficiency is improved through reformation of the governing expressions in vector and non-vector components. The fluxes across cell surfaces are computed as part of the vector computation through linearization of the flux terms.

This linearization is achieved through estimation of neighbour states based on local conditions. The method, named SHLL, is accordingly very efficient on vector computation architectures and also well suited to modern CPU’s with AVX extensions. Here, real-time visualization of the results is possible due to transformation of the CUDA variables used in the solution into OpenGL data directly.

(This video is captured from a real-time simulation and visualizatio.)

視覺化大量且隨時間變化之容積資料(Visualize Large Time-Varying Volume)

本研究由交大資工 Computer Graphics Geometry Modeling 實驗室與國網中心視算與互動媒體實驗室合作完成，目的在於視覺化高解析度且隨時間變動之大型容積資料。

我們使用多層次精細度（Level-Of-Detail）的觀念處理旁大容積資料，再使用類似視訊的方法處理時間軸上資料的變化。此系統結合了 Wavelet、Octree、 Motion Compensation、Hardware Texture Mapping、Spatial Region of Interest、Temporal Region of Interest、Caching、Pre-loading等方法，使得大型容積資料達到即時互動之播放效果。

附註：

1. This data set is made available by Dr. Jacqueline Chen at Sandia National Laboratory through SciDAV IUSV, and we re-sample this data set into 8 (2x2x2) times of the original.
2. 本研究部分經費由國科會計畫 NSC 95-2221-E-492-007 支援。

水流模擬（Water Flow Simulation）

高速電腦中心流體力學小組之水流模擬視覺化結果。我們將流體力學小組使用超級電腦所作之水流模擬計算，進行四維的動態視覺化展示。

裕隆汽車衝撞模擬（Yulon Car Crash Simulation）

裕隆汽車之物理碰撞模擬視覺化結果。此展示透過高速電腦計算裕隆汽車的物理碰撞模擬，然後將電腦所算出的模擬碰撞過程進行四維的動態展示。