טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMindelis Ya'akov
SubjectVolumetric Graphical Flow Visualization
DepartmentDepartment of Aerospace Engineering
Supervisor Dr. Yuval Levy


Abstract

A new technique for the volumetric visualization of complex flow fields is presented. The method utilizes the Volumizer extension of OpenGL together with the extension of the Fast Line Integral Convolution algorithm (FLIC) to three-dimensions to create a complete volumetric representation of the flow field. The method allows the simultaneous representation of one vector field along with two scalar fields. One scalar field is represented using a color-map while the second scalar field is reflected through the opacity levels using specially designed transfer functions. Appropriate choice of the transfer functions allows to see the whole three-dimensional flow field. In this work the FLIC algorithm is further extended by utilizing a dynamic convolution kernel length scheme that is based on the geometrical properties of streamlines.

The implementation of the new method is conducted by means of a computer program that contains a Graphic User Interface (GUI). The GUI allows interactive visualization sessions where all visualization parameters are accessible to the user and most of them can be controlled interactively using mono- or stereoscopic display that adds the depth element to the scene.

The motion is introduced into the visualization scheme via an animated representation. The new method utilizes two types of animation techniques: velocity vector field animation using Frame Blending technique of the FLIC texture and animation via gradual changes of the view-port or opacity parameters.

Two examples are presented in this work. The artificial data contains a vortex like flow and is used to demonstrate the influence of various visualization parameters.

The numerical solution of the flow about the hemisphere cylinder is used to show the remarkable ability of the new method to extract important flow field features such as the lee-side vortices.