flow visualization cs 4390/5390 data visualization shirley moore, instructor november 24, 2014 1
TRANSCRIPT
Announcements
• Tests will be graded by next Monday, can do retake finals week if needed
• Project design documents are due today. Turn in tomorrow (Tuesday) by midnight in order not to lose points (turn in hard copy or email to [email protected])
• Final exam period is Friday, December 12, 1:00-3:45pm; Final projects are due then.
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Understanding Fluid Flows
• Dynamics causing the flow (forces)– Pressure, buoyancy, inertia, viscous
forces, surface forces…. Etc.
• Effects of these forces on the flow (Flow and fluid properties)– Velocity, acceleration, vorticity– Viscosity, temperature, scalar
concentration, density …. Etc.
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Why Flow Visualization
• Understand flow phenomena• Verify model or theory results• Easier measurements• To get a priori knowledge of a
solution
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What we need to visualize
• Stream lines– a line, tangent to which at any given instant
is the velocity vector at that point
• Streak lines– locus of particles which have passed through
a prescribed point during a specified time interval
• Path lines– locus of points traversed by a given fluid
particle during some specified time interval
• Time lines– line joining different adjacent points at any
instant of time5
Methods of flow measurement
• Gas flows– Smoke visualization– Particle– Shadowgraphs and Schlieren
• Liquid flows– Dye– Shadowgraphs and Schlieren– Particles– Bubbles– Fluorescence, phosphorescence
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Some gas flow visualization images
Smoke visualization
Top- flow past aerofoilSide- laminar smoke jet
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Jets and Plumes
•Top left- flow below an ice cube in water
•Top right- near field of a jet
•Side- jet and flame jet
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Computational Fluid Dynamics
• Simulates fluid flow by solving differential equations using numerical methods
• CFD has taken the place of wind tunnels for many evaluations of aircraft and, as computing power increases and computer models become more sophisticated, CFD will largely replace wind tunnels.
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Streamlines, Pathlines, and Streaklines
• Streamlines– https://www.youtube.com/watch?v=TOUylg7Eyec
• Pathlines– https://www.youtube.com/watch?v=ZRUYHQCQLBk
• Streaklines– https://www.youtube.com/watch?v=UqHd3pnEKtA
• Popular streamline, pathline, streakline videos– https://www.youtube.com/playlist?
list=PLvQKTRyZQ7uKIUcYY2bnQh0Hqx2lVDAub
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Flow Visualization Examples
• NASA– http://www.grc.nasa.gov/WWW/k-12/airplane/tunvis.html
• Flometrics– http://www.flometrics.com/fluid-dynamics.shtml
• Flow visualization course at University of Colorado– http://www.colorado.edu/MCEN/flowvis/galleries/
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