Facilities & Equipment at the Christopher and Susan Burke H2O Laboratory

The Christopher and Susan Burke Hydraulics and Hydrology Laboratory at Purdue is equipped with a collection of research and teaching facilities and instrumentation to address water-related research challenges:

• Laboratory flumes and tanks (including 150ft long towing tank)
• Laboratory instrumentation
• Field equipment (including autonomous underwater vehicle)
• Computational resources (including water visualization studio)
• Teaching facilities (including wet classroom)
• 3-story Loganathan Waterfall

Laboratory flumes and tanks

Tilting Open Channel Flume - The laboratory has a 40foot long, 1ft wide open channel flow facility for investigations of river flow and sediment transport. It can be lined with either a fixed bottom or movable sediment bed. A closed-loop pump control system maintains a constant flow rate for experiments, and the flume can be tilted over a wide range of bed slopes. Contact Prof. Dennis Lyn for more information on this facility and its research.

Large Stratified Flows Facility - For investigations targeting fluid systems with variable densities (such as the ocean and temperate lakes), the lab has a large-scale stratified flows facility. This Purdue facility is a 0.6m wide, 0.6m tall facility with a 10m test section that was custom fabricated by Armfield, Inc. (UK) for the PI. The facility has glass walls for all of the test section faces, and instrument rails above and below the channel. The facility can be used either as an enclosed tank, as it is for internal wave experiments, or as a re-circulating flume. The pumping capabilities of the flume are nearly 120 liters/sec. The facility is equipped with a set of bottom diffuser ports through which saline fluid can be injected, in order to density-stratify the tank, as well as a selective withdrawal device to allow for repeated experiments with nearly identical stratifications. The facility is housed in a specially-constructed temperature- and light- controlled enclosed room to tightly control the experimental conditions, and de-ionized water is used to fill the facility.

Purdue towing tank - The Purdue Towing Tank is a 150ft long, 11ft wide, and 5ft deep water basin used for hydrodynamics research. The tank is equipped with an overhead towing carriage, a water filtration system, viewing ports to obtain flow images, underwater load cells, and a suite of underwater pressure transducers. There are plans to convert this facility into a wave basin.

Laboratory Instrumentation

Particle Image Velocimetry (PIV) - Planar velocity measurements are obtained using a particle image velocimetry (PIV) system. The system, currently mounted to the stratified flows facility, can traverse the length of the facility, allowing for detailed velocity measurements in any 2-D vertical plane. A 120MJ Nd-YAG laser forms the light basis of the system, and timing is accomplished using a LabVIEW program. Images are captured using an 8-bit RedLake MegaPlus ES 4.0 camera, allowing for a maximum frame rate of 5 image pairs/sec. Image processing is carried out using MatPIV, freely available PIV software developed by J. Kristian Sveen. Image calibration is accomplished by imaging a scored target placed in the imaging plane; standard mapping procedures are used to rectify velocity measurements taken when the camera is placed at an angle to the laser light sheet. The system has been validated with detailed measurements of a fully-developed turbulent channel flow.

Planar Laser-Induced Fluorescence (PLIF) - A Planar Laser-Induced Fluorescence system is nearly complete on the stratified flows. This system is based on the scalar imaging techniques developed by Prof. Cary Troy and his Stanford collaborators (Crimaldi and Koseff 2001; Troy and Koseff 2005). For this technique, a laser-fluorescent dye (typically Rhodamine 6G) is seeded into the flow; calibrated images of laser-induced dye fluorescence, properly calibrated, then yield quantitative images of scalar concentrations. For the present application, dye is seeded similarly in the flow facility as is saline fluid, and thus dye fluorescence can be converted via calibration to 2-D images of salinity (salt and Rhodamine 6G have nearly identical diffusivities, Sc=600). The laser light sheet is generated using a scanning mirror (Cambridge Technologies) that is driven by an analog signal sent from a PC; optics focus the laser light sheet (Coherent Innova 5W Argon Ion) to approximately 0.2mm, and it is this thickness of the light sheet that sets the resolution of the system.

Other Laboratory Instrumentation - The laboratory is equipped with a host of additional laboratory instrumentation including pointwise acoustic velocimeters, strain gages, data acquisition cards, a 1-D Laser-Doppler-Anemometer for velocity measurements, and more.

Field equipment

The lab has a large collection of instrumentation for use in field studies, including:

• Campbell Scientific Weather Station: equipped with a cellular modem, capable of measuring air temperature/humidity, wind speed and direction, and other parameters of interest.
• Sontek Acoustic Doppler Profiler: This 3000MHz shallow-water current profiler has a range of 6m and is suitable for continuously measuring velocity profiles in lakes and rivers. It is deployed frequently in Lake Michigan.
• Sontek Acoustic Velocimeters (2): The lab has two Sontek velocimeters for point-wise velocity measurements in the laboratory or field.
• Temperature Loggers (>50): The laboratory has more than 50 temperature loggers for use in field studies, including HOBO pro-V2 loggers, RBR high-resolution loggers, and SeaBird sensors.
• Moorings: Numerous buoys, subsurface floats, and hardware are available to place moored instruments in depths up to 100m of water.

Autonomous Underwater Vehicle (AUV) - The lab has a YSI EcoMapper, an underwater autonomous vehicle designed to sample various water quality parameters with primarily optical sensors. The autonomous underwater vehicle is the newly-released YSI EcoMapper, a self-powered, self-logging vehicle that can be programmed to perform water quality surveys to map temperature, depth, distance from bottom, dissolved oxygen, conductivity, pH, blue-green algae, Chlorophyll-a, Rhodamine WT, and turbidity. All sensors, when used in this configuration, have a relatively fast response time (typically several seconds or less), making the vehicle suited for ~10m scale resolution mapping over large distances. The vehicle is deployed from shore or from a small boat with 1-2 people, weighing only 50 pounds, and can travel at speeds of 1-4 knots (0.5-2 m/s) for approximately 8-10 hours on a single charge. The vehicle navigates using a combination of bottom tracking, GPS, and dead reckoning, and has a location pinger in the event it becomes lost. The EcoMapper is ideally suited to Lake Michigan's currents, which are typically less than 10cm/s during the spring to fall period. The vehicle is also frequently utilized in outreach demonstrations to the public and school groups. Contact Professor Cary Troy for more information.