Fluid Mechanics Measurement Instrumentation

David Sumner, Ph.D., P.Eng., Professor

Department of Mechanical Engineering, University of Saskatchewan

 
 
Overview

The complex flow fields being studied (strongly three-dimensional, separated, inherently unsteady or periodic, turbulent, wide range of length and time scales) pose significant challenges for measurement and modeling. A wide selection of measurement instrumentation is available in the Department of Mechanical Engineering for experimental fluid mechanics research. This selection includes six-component force balances, pressure transducers and pressure probes, multi-channel hot-wire anemometry (HWA), laser Doppler velocimetry (LDV), and particle image velocimetry (PIV).  The instrumentation is used with the Low-Speed Wind Tunnel, the X-Y Towing Tank, and in other laboratory facilities.  LabVIEW software and high-speed data acquisition and motion control hardware are used with both facilities.

 
 
Data Acquisition and Motion Control Systems

Measurements are made with National Instruments 16-bit high-speed computer data acquisition systems and personal computers.  Automated experiments (probe and model positioning systems, towing systems) use multi-axis motion control systems (with stepping motors and micro-step drivers).  The data acquisition and motion control software is written in the National Instruments LabVIEW graphical programming language.  Origin and Tecplot data analysis and presentation software are available.

 
 
Flow Visualization Methods

Several flow  visualization techniques and equipment that are available include aluminium dust surface flow visualization (with the X-Y Towing Tank), dye injection , fog generator (with the Low-Speed Wind Tunnel), laser light sheet flow visualization, and digital still and video cameras.

 
 
Force Measurement Systems

In the Low-Speed Wind Tunnel, aerodynamic forces can be measured with an ATI Industrial Automation "Gamma" six-component force balance.  A large six-component balance is also available (manufactured by Engineering Shops).  An ATI Industrial Automation "Mini" six-component force balance has been acquired for the X-Y Towing Tank.

 
 
Pressure and Temperature Measurement Systems

Datametrics Barocel, Edwards and Validyne absolute and differential pressure transducers are used with the Low-Speed Wind Tunnel.  Two Scanivalve ZOC-17 pressure scanners are also available.  Several types of temperature and humidity sensors are used.  Our calibration lab has a Meriam Micro-Manometer, which is used to calibrate our pressure transducers.  Selected models of pressure transducers available include the Validyne DP15 pressure sensor (with CD15 carrier demodulator) and the Validyne P55D differential pressure transducer.

Pressure and Velocity Measurement Systems

The Low-Speed Wind Tunnel has an automated, three-axis probe positioning system, which was manufactured by Engineering Shops.  Pressure probes and hot-wire probes can be installed in the system's probe holder.  Pressure-based velocity measurement techniques used with the Low-Speed Wind Tunnel include boundary layer, Kiel, Pitot, and Pitot-static probes (manufactured by Engineering Shops and United Sensor).  A seven-hole pressure probe manufactured by Engineering Shops is used for wake surveys. For turbulent velocity measurements in the Low-Speed Wind Tunnel, there is a Dantec Dynamics StreamLine six-channel HWA system.  A wide selection of probes is available (single-wire, single-film, x-wire, x-film, triple-wire, boundary layer, surface-mounted hot-film sensor, etc.).  A Dantec Dynamics automated multi-component probe calibrator is used for calibrating the seven-hole pressure, x-wire, and triple-wire probes.  A two-component LDV system, manufactured by Dantec Dynamics, is also used for turbulent velocity measurements in air and water flows.  For whole-field velocity measurements in water and air flows, a TSI llow-frame-rate stereoscopic PIV system is available.  An in-house conventional, two-dimensional, low-frame-rate PIV system developed by my colleague, Dr. Jim Bugg, is also used. Other instruments available include vane anemometers (wind speed measurements), a turbine flow meter (stream flow measurements), and MKS mass flow controllers.

 
 
Large Eddy Simulation (LES)
Under the leadership of my colleague, Dr. Don Bergstrom, a numerical modeling approach is also be pursued for the analysis of flows around surface-mounted, finite-height prisms.  This uses an in-house large eddy simulation (LES) computational fluid dynamics (CFD) code, which has been developed by Dr. Bergstrom and his students over the years.  This code uses advanced subgrid-scale (SGS) modeling techniques.
 
 

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Last updated: November 5, 2012