Replacement of laser and PM tubes in the laser doppler velocimeter system at the university of windsor

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Discharging water, wastewater and industrial effluents (liquids & gases) into the natural system such as rivers, lakes, oceans and the atmosphere is a major way of disposing pollutants.  The ability to model these flow systems and the associated transport is of critical importance in environmental applications.  In most cases, the flows are turbulent, which means the mixing is largely due to small-scale chaotic behaviour of the fluid.  The mass transport and dilution of pollutants is essentially controlled by turbulence.  The flow fields are complex with the flow changing direction quite often.  To better understand and control many of the above mentioned processes, knowledge of the velocity field is an essential ingredient.  Research in this area is progress at the University of Windsor and a significant contribution has been made over the last five years using a laser Doppler velocimeter (LDV).  The LDV system has unique advantages: non-invasiveness, no calibration, no drift, very fast data acquisition and importantly, the LDV system can detect changes in flow direction. The proposed equipment grant is requested to support the replacement of the laser and the photomultiplier (PM) tubes in the existing LDV system.  The LDV system was purchased five years ago with a 300 m-W air-cooled laser and two PM tubes at a cost of $ 100,000.  The LDV system is used extensively by students, visiting faculty, post-doctoral fellows and faculty members at the University of Windsor.  Seven students have completed their theses in the past three years. The laser, which has a limited life was refurbished two years ago.  Presently the system is non-operable due to the failure of the laser and the two PM tubes.  Both these components are consumable items and need to be replaced.  There is an immediate need for this as four students from two departments need to use the system for the following projects: effect of roughness in open channel flows, (2 PhD students), hydraulic model studies (1 MASc student) and jet studies ( 1 MASc student)