Instructor: Lichuan Gui Imaging Techniques for Flow and Motion Measurement Engr 699, Section 81 Instructor: Lichuan Gui Spring Semester 2011 Tuesdays and Wednesdays 2:00-3:15pm NCPA class room #1128 Class material available at http://lcgui.net/index_files/Page946.html EDPIV software available at http://edpiv.com

Fluid Flow Measurement Methods Overview Imaging Techniques for Flow and Motion Measurement Lecture 1 Fluid Flow Measurement Methods Overview Lichuan Gui University of Mississippi 2011

Discussion Why do fluid flows need to be measured?

Discussion What variables need to be measured? Velocity Pressure Temperature Density ?

Discussion Non-imaging measurement techniques: Velocity: U-tube manometer Pitot probe Hot wire/film anemometer (HW/ HF) Laser Doppler velocimetry/anemometry (LDV /LDA) Sonic anemometer Pressure: pressure sensors Temperature: temperature sensors Density: reduced from P, T etc.

Non-imaging Techniques Velocity measurement using U-tube manometer - Calibration required to determine coefficient “c”

Non-imaging Techniques Velocity measurement using pitot probes 2-hole pitot probe (1D) 3-hole pitot probe (2D) 5-hole pitot probe (3D)

Non-imaging Techniques Velocity measurement using HW & HF Hot wire Hot film Hot film

Non-imaging Techniques Velocity measurement using HW & HF Energy balance Electric resistance Heat convection coefficient Flow velocity - Different systems: CCA, CVA, CTA - Calibration required 9

Non-imaging Techniques Laser Doppler Velocimetry/Anemometry

Non-imaging Techniques Summary of the velocimetries Pitot proble, HW & HF Point-by-point measurement Intrusive Calibration required LDV (LDA) Non-intrudsive No calibration

Imaging Techniques Three groups of flow visualization methods Foreign material added to the fluid flow Optical methods sensitive to refraction index changes Foreign energy (e.g. heat or electric discharge) added to the fluid flow

Imaging Techniques Visualization of flow direction Example: Dye lines in water flow Vortex flow behind a yawed cylinder visualized with mixture of ink, milk and alcohole

Smoke lines around an airfoil model in a wind-tunnel Imaging Techniques Visualization of flow direction Example: Smoke lines in air flow Smoke lines around an airfoil model in a wind-tunnel

Imaging Techniques Visualization of flow direction Example: Tuft Screen Trailing vortices behind an inclined delta-wing as visualized by a tuft screen

Imaging Techniques Velocity measurement with tracers Example: Hydrogen-bubble technique Consecutive rows of hydrogen bubbles indicating Velocity profiles a flat plat boundary layer

Stroboscopic illumination of oil drop in laminar pipe flow Imaging Techniques Velocity measurement with tracers Example: Small particles Stroboscopic illumination of oil drop in laminar pipe flow

Shadowgraph of a sphere flying at M=1.7 Imaging Techniques Optical methods for compressed flows Shadowgraph Shadowgraph of a sphere flying at M=1.7

Schlieren photograph around a sphere flying at hypersonic speed Imaging Techniques Optical methods for compressed flows Schlieren Method Schlieren photograph around a sphere flying at hypersonic speed

Imaging Techniques Other methods Summary X-ray & Echo PIV Molecular Tagging Velocimetry (Seedless velocimetry) Laser Speckle Photography Temperature measurement with particle Brownian motion More Summary Full-field measurement (2D & 3D) Non-intrusive