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

将水、废水和工业废水(液体和气体)排放到河流、湖泊、海洋和大气等自然系统中是处理污染物的主要方式。能够对这些流动系统和相关的传输进行建模在环境应用中至关重要。*在大多数情况下，流动是湍流的，这意味着混合很大程度上是由于流体的小范围混沌行为。尽管污染物的质量传输和稀释基本上是由湍流控制的。尽管流场是复杂的，流动方向经常改变。为了更好地了解和控制上述许多过程，对速度场的了解是必不可少的因素。温莎大学在这方面的研究取得了进展，在过去五年中，使用激光多普勒测速仪(LDV)做出了重大贡献。LDV系统具有独特的优势：非侵入性、无校准、无漂移、非常快速的数据采集，重要的是，LDV系统可以检测到流动方向的变化。建议的设备拨款是为了支持更换现有LDV系统中的激光器和光电倍增管。*LDV系统是五年前购买的，配备了一台300米瓦的风冷激光器和两根PM管，耗资10万美元。*LDV系统被温莎大学的学生、访问教员、博士后研究员和教职员工广泛使用。在过去的三年里，有七名学生完成了他们的论文。该激光器的寿命有限，两年前进行了翻新。目前，由于激光器和两个PM管的故障，系统无法运行。但这两个部件都是消耗品，需要更换。现在有迫切的需要，因为来自两个系的四名学生需要使用该系统进行以下项目：明渠水流中粗糙度的影响(2名博士生)、水力学模型研究(1名MASC学生)和喷流研究(1名MASC学生)

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)