Operation

Installation

Tools and parts needed

• 8 mm, 1/4 inch drive hex key
• Torque wrench with 70 Nm capacity—either 1/4 inch drive or adapted down to 1/4 inch
• 1/4 inch ratchet
• Bar clamp
• 9/16 inch ratchet wrench or socket
• 5 mm, 1/4 inch drive hex key
• Necessary parts are kept in a plastic container labeled "Turbine test bed" stored on the control platform shelves.

Mechanical

This process should take two people about one hour to complete. Note: The beach must be installed before the tow frame can be installed.

1. Install turbine in test bed frame assembly while on its rolling stand.
2. On the tow carriage, move drag slides (mounted below carriage) out to the outer edge of the carriage on the beach side by loosening the top 8 socket-head cap screws on each side with a 5 mm hex key.
3. Home the tow axis. This will make the tow carriage stop at the limit switch. Back up the tow carriage until there is approximately 0.7–1.0 m between the ends of the beach and the edge of the tow carriage.
4. Lift frame with beach gantry hoists and move towards the carriage. CAUTION: When lifting, make sure tow frame and turbine clear tank walls, make sure lift hooks are installed such that steel cables do not cross.
5. Lower frame and insert the 3/8-24 hex bolts through the upper clevis brackets, through the rod end at the top of the frame. Tighten these by hand.
6. Take load off gantry hoists.
7. Swing lower drag slide arms downward to engage with the self-clinching nuts on the vertical foil sections of the main frame.
8. Insert and tighten the 3/8-16 hex bolts through the lower clevis bracket and the self-clinching nuts.
9. Slide the frame back under the carriage, towards the wavemaker, until the front edge of the front drag slide mounting plates are aligned with the mark on the carriage's 80/20 members. This mark should be 24" from the beach end of the 80/20 extrusions, for reference. See Figure 1 for details.
10. Attach a bar clamp to the bottom of the 80/20 extrusions mounting the drag slides and pull them up flush against the top 80/20 extrusions attached to the tow carriage. Tighten the 8 screws on each side using a 5 mm hex key.
11. Attach outer guy wires to outer linear bearings and tension by hand. Be sure to tension uniformly so the frame remains square and vertical.
12. Attach inner guy wires. This involves turning the cable end counterclockwise roughly 5 turns before engaging the threads so that the torsion preload tensions the cable as it unwinds in the clockwise direction while threading into the rod end at the drag slide.
13. If taking wake measurements install the YZ traverse.

Figure 1: Drag slide (right) mounting distance.

Connecting instrumentation

Connect torque and drag measurement instrumentation cables to the modules installed in the NI CompactDAQ according to the following table:

Sensor	NI module	Phys. chan.
Torque trans.	NI-9205	0
Torque arm	NI-9237	0
Drag left (facing beach)	NI-9237	1
Drag right (facing beach)	NI-9237	2

Installing servo motor

1. Turn off the onboard electronics cabinet using the disconnect handle on the front of the door.
2. Slowly drop motor into position such that the flexible coupling engages with the torque transducer.
3. Insert and tighten 4 socket head cap screws with an 8 mm hex key socket on a 1/4 inch ratchet.
4. Torque flexible coupling screws to 70 Nm to clamp onto the torque transducer shaft.
5. Attach servo cables to motor and the beach-facing side of the onboard electronics cabinet. Note: the connectors on the motor-ends of the cables are similar, and pin damage can occur if these are mismatched. The power cable mates to the "MOTOR POWER" connector and feedback cable mates to the "MOTOR FEEDBACK" connector on the cabinet.
6. Turn on the onboard electronics cabinet and restart the controller via SPiiPlus MMI Application Studio (on the Tow Tank PC).

Running

Pre-run checklist

1. Check that the tank depth is 2.44 m and fill or drain as necessary.
2. Home tow axis. This should have been done as part of the installation process, but must be repeated each time the controller is restarted, e.g., when starting a new day of runs.
3. Launch the TurbineDAQ application. See the TurbineDAQ wiki for more information.
4. With the turbine axis disabled, rotate turbine by hand to an azimuthal angle of zero, then home the turbine axis from the TurbineDAQ "Homing" menu.
5. If taking Vectrino measurements, home the y- and z- axes from the TurbineDAQ "Homing" menu.
6. Ensure the NI DAQ and Vectrino (if applicable) are powered on.
7. Select the experiment working directory using the folder icon next to the address bar. If test matrix CSVs are located in the appropriate directory, these will be loaded automatically into the test plan table.
8. Using the icons in the TurbineDAQ toolbar, check that each DAQ system (ACS motion controller, NI, and Vectrino) can acquire data. Signals will be plotted as they are acquired.
9. Move the tow axis back to zero using the Tow application or the SPiiPlus MMI Application Studio terminal with the command ptp tow, 0.
10. Ensure that the carriage path is clear.
11. Switch to shakedown mode and select some conservative parameters for an initial test run, e.g., a tow speed of 0.5 m/s or so.
12. Perform a shakedown run. If the experiment processing software has been setup correctly, the run will be processed automatically and the results printed to the terminal.

Seeding the tank

Note: This is only necessary if taking velocity measurements with the Vectrino.

1. Mix approximately 1 cup of 11 micron mean diameter hollow glass spheres with approximately 1 gallon of water.
2. Using the Tow application, turn on the jog pendant.
3. While on board the carriage, jog to the beach end of the tank.
4. Jog the tank slowly towards the wavemaker, pouring the seeding mixture into the center (cross-stream direction) of the tank.
5. Return to the control platform and perform a couple turbine tows at ~1 m/s, either as a TurbineDAQ shakedown run, or using one of the motion control buffers via SPiiPlus MMI Application Studio.
6. Using the Nortek Vectrino Plus application or the TurbineDAQ Vectrino monitoring feature, sample velocity data and observe the signal-to-noise ratio (SNR) and correlation values. Continue adding seeding and mixing until the SNR reaches approximately 12 dB. Note that the YZ traverse axes should be disabled while the Vectrino is sampling.

Determining tank settling time

Before undertaking regular performance and wake measurement runs, tank settling times should be established. In principle this should only need to be done once for each turbine. TurbineDAQ is setup to perform "settling runs," the test matrix for which is tabulated in Config/Test plan/Settling.csv, where a turbine is towed and returned to the control platform. The Vectrino will then acquire wake data for an extended period of time. This data can then be inspected manually to determine when mean and turbulence quantities have decayed below an acceptable threshold. After determining a settling time (in seconds) for each speed, TurbineDAQ will automatically read these values from the Config/settling_times.csv file. For an example, see Settling.csv from the RM2 tow tank experiment repository.

Acquiring performance and wake data

If test matrix sections have been loaded properly, and settling times have been tabulated in the correct file, pressing the "play" icon in the TurbineDAQ toolbar with the "Test Plan" tab visible will start the next unfinished run in the table. So long as the "play" button is depressed, TurbineDAQ will continue executing runs, idling in between according the specified settling times.

Acquiring tare torque data

1. Move the carriage to the beach end of the tank near the gantry hoists.
2. Remove the turbine and mounting frame from the carriage. See below for removal instructions.
3. With the frame suspended out of the water by the gantry hoists, remove the turbine blades.
4. Reinstall the servo motor and cables (note that the onboard electronics cabinet should be turned off whenever plugging or unplugging cables).
5. Switch to the Tare torque test matrix section from the "Test Plan" tab in TurbineDAQ.
6. Ensure the turbine shaft is free to rotate, and press the "play" icon in the TurbineDAQ toolbar. Similar to the standard performance and wake measurement runs, the table will be executed automatically.

Acquiring tare drag data

1. After acquiring tare torque data (see above), remove the turbine shaft from the frame.
2. Remove the servo motor and place back at the control platform. Note that the ACS motion controller will need to be restarted after turning the onboard electronics cabinet on/off.
3. Reinstall the turbine mounting frame under the carriage and attach all four guy wires.
4. Switch to the Tare drag test matrix section from the "Test plan" tab in TurbineDAQ.
5. Ensure the carriage path is clear, and press the "play" icon in the TurbineDAQ toolbar. The table of tare drag runs will then be executed automatically.

Removal

1. Turn off the onboard electronics cabinet.
2. Disconnect the torque arm and torque transducer sensor cables. Coil up and wrap around the torque arm load cell mounting bracket.
3. After at least 10 mins with the electronics cabinet powered-off, remove the servo cables and put these back on the shelf on the control platform.
4. Loosen but don't remove the bottom two screws of the upper flexible servo coupling (the one torqued to 70 Nm during installation.
5. Remove the four socket head cap screws fixing the servo gearhead to the torque arm mounting block.
6. Pull up to remove the servo and gearhead, then place this on the small desk in the corner of the control platform.
7. Remove all four guy wires and attach these back to the frame, as it was in storage.