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Novel Visualization and Interaction Techniques for Gaining Insight into Fluid Dynamics in Internal Combustion Engines
Summary:	Future emission regulations and increased customer demands require the utilization of all available tools in developing engines of the next generation. 3D CFD simulation is one of these tools. Due to well-advanced and well-developed simulation technology and improved computing power, the generated pack of data becomes complex and difficult to evaluate. In principle, technical problems can be treated with simulation, but the analysis of data very often leads to unsatisfactory results due to the limited evaluation functionality of the tools available at present. On the one hand, the reason is to be found in the visualization of 3D data, which is nowadays almost always performed in 2D only, and on the other hand in the physical relation of parameters, which is usually not reproduced in the analysis. Recently developed visualization techniques and modern graphics hardware make it possible to interact with vast amounts of multidimensional data in an intuitive way. A novel approach called SimVis allows the engineer to specify certain subsets of the data - so-called features - in terms of data attributes under consideration (e.g., pressure, temperature, etc., and combinations thereof) and to immediately get a 3D view of the CFD data set with the selected features highlighted. This is useful to understand statistical properties of the data and the corresponding spatial and temporal distribution. Geometric properties can be presented and explored by means of virtual reality (VR) methods, which allow the user to become immersed in the dataset and to interact with the model in a natural way. Progress in PC graphics hardware technology makes it possible to perform sophisticated tasks in real-time in such an environment. By a simulation of a scavenge and combustion process in a 2-stroke engine, this paper investigates new solutions to the evaluation and visualization problem using SimVis and VR. Moreover, an outlook on further new developments is given.
Project partners:	This work is a joint project which was carried out by Stephan Schmidt, Oliver Schögl, and Roland Kirchberger from the Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology, Austria Helmut Doleisch, Philipp Muigg, and Helwig Hauser from the VRVis Research Center, Vienna, Austria Markus Grabner, Alexander Bornik, and Dieter Schmalstieg from the ICG Institute for Computer Graphics and Vision, Graz University of Technology, Austria
Papers:	More details about this work can be found in a paper, which has been accepted for publication in the Proceedings of the NAFEMS World Congress 2005, which will be held in May 2005 in Malta. Below images on this webpage are taken from this paper.
Images/Results: (to retrieve an enlarged version of the images, click on them)		Figure 1: (left) Calculation mesh of a cylindrical volume; (right) section with impressed variable (colour = equivalence ratio)
		Figure 2: a typical multi-view setup for a visual analysis session with SimVis (engine data)
		Figure 3: Principle sketch of a loop-scavanged two-stroke engine (A...exhaust, E...intake)
		Figure 4: (left) Calculation mesh of the two-stroke simulation; (right) average ER of a volume of 5mm radius around the spark plug versus the time
		Figure 5: Definition of feature set: (left) equivalence ratio versus time; (right) mass fraction O2 versus time
		Figure 6: Equivalence ratio at 360°CA for (left) high injection rate; and for (right) low injection rate
		Figure 7: Equivalence ratio at (left) 210°CA; and at (right) 340°CA
		Figure 8: (left) Handling of the 3D mesh of a two-stroke cylinder; (right) investigation of the velocity of the fluid motion using sections on the PIP
		Figure 9: Investigation of details of the mesh using the "zoom"-function and the PIP
	This page is maintained by Helmut Doleisch.  In case of questions, comments, etc., please mailto:Doleisch@VRVis.at.