2015.02.19


In [1]:
# Standard setup block for running Python code
from __future__ import division, print_function
import os
if os.path.split(os.getcwd())[-1] == "Lab notebooks":
    os.chdir("../../")
    print("Moved to experiment root directory")
from Modules.processing import *
from Modules.plotting import *
plt.style.use("Config/plotstyle.mplstyle")
%matplotlib inline


Moved to experiment root directory

Daily checklist

  • Check tank depth and correct if necessary.
  • Home turbine axis.
  • Home tow axis.
  • Home y-axis.
  • Home z-axis.
  • Wipe any corrosion from turbine mounting frame.
  • Seed and mix tank until Vectrino SNR is approximately 12 dB.

Started at 11:30 AM.

Torqued upper curved jaw servo coupling. Wiped corrosion from turbine mounting frame.

Homed turbine axis.

12:06 PM -- Filled tank about 2 mm to reach 2.44 m depth. Starting strut torque runs with covers.

12:14 PM -- Rotated turbine at 20, 40, 60 RPM to see how things look. At 60 RPM, there is a noticeable flow at the surface, but torque looks fairly constant--about 35 Nm.

12:17 PM -- Homed y- and z-axes.

12:21 PM -- Starting Strut-torque-covers.

12:49 PM -- Finished Strut-torque-covers. Peak torque was about 80 Nm.

1:10 PM -- Did dummy tow with strut covers and no blades. Torque was around -30 Nm max.

1:24 PM -- Mixed up tank and did another 2 dummy tows.

1:35 PM -- Added a cup of seeding to the tank since we are doing wake measurements for the runs with no blades.

1:37 PM -- Starting Perf-1.0-no-blades-covers.

Looks like we add about 10 Nm of parasitic torque when towing.

4:05 PM -- Finished Perf-1.0-no-blades-covers. Backing up data.

4:59 PM -- Reinstalled turbine with no blades or strut covers.

5:25 PM -- Re-homed all axes. Starting Perf-1.0-no-blades.

7:53 PM -- Completed Perf-1.0-no-blades. Backing up data.


In [15]:
process_strut_torque(23, plot=True, verbose=True, covers=True)


Processing strut torque with covers run 23
Reference TSR = 4.5016
Strut torque = -62.6292293814 Nm at 79.9758902571 RPM
Out[15]:
(4.5015924082197607, 1.2304794493924431)

In [12]:
tsr_ref = []
cp_loss = []
for n in range(26):
    tsr, cp = process_strut_torque(n, covers=True)
    tsr_ref.append(tsr)
    cp_loss.append(cp)
    
plt.plot(tsr_ref, cp_loss, "-o") 
plt.xlabel("$\lambda$")
plt.ylabel("$C_P$ loss estimate")
plt.show()



In [59]:
# Calculating tare torque test matrix for experiment
def calc_rpm((tow_speed, tsr)):
    omega = tsr*tow_speed/R
    return omega/(2*np.pi)*60.0

save = False
lowest = (0.2, 1.0) # tow_speed, tsr
highest = (1.4, 4.0)

rpm_start = calc_rpm(lowest)
rpm_end = calc_rpm(highest)

steps = 25

rpms = np.linspace(rpm_start, rpm_end, steps)
revs = np.ones(len(rpms))*30.0
revs[0] = 4
revs[1] = 8
revs[2] = 12
revs[3] = 16
revs[4] = 20
revs[5] = 24
revs[-1] = 32

df = pd.DataFrame()

df["rpm"] = rpms
df.index.name = "run"
df["revs"] = revs
if save:
    df.to_csv("Config/Test plan/Tare-torque.csv")
df["minutes"] = revs/rpms
df["samples"] = np.floor(df.minutes*60*2000)
df["samples_per_rev"] = df.samples/df.revs
print("Total time (minutes):", df.minutes.sum())
df


Total time (minutes): 16.6644519302
Out[59]:
rpm revs minutes samples samples_per_rev
run
0 3.553227 4 1.125737 135088 33772.000000
1 7.550607 8 1.059518 127142 15892.750000
2 11.547987 12 1.039142 124697 10391.416667
3 15.545367 16 1.029246 123509 7719.312500
4 19.542747 20 1.023398 122807 6140.350000
5 23.540126 24 1.019536 122344 5097.666667
6 27.537506 30 1.089423 130730 4357.666667
7 31.534886 30 0.951327 114159 3805.300000
8 35.532266 30 0.844303 101316 3377.200000
9 39.529646 30 0.758924 91070 3035.666667
10 43.527026 30 0.689227 82707 2756.900000
11 47.524406 30 0.631255 75750 2525.000000
12 51.521786 30 0.582278 69873 2329.100000
13 55.519166 30 0.540354 64842 2161.400000
14 59.516546 30 0.504062 60487 2016.233333
15 63.513926 30 0.472337 56680 1889.333333
16 67.511306 30 0.444370 53324 1777.466667
17 71.508686 30 0.419529 50343 1678.100000
18 75.506066 30 0.397319 47678 1589.266667
19 79.503446 30 0.377342 45281 1509.366667
20 83.500826 30 0.359278 43113 1437.100000
21 87.498206 30 0.342864 41143 1371.433333
22 91.495586 30 0.327885 39346 1311.533333
23 95.492966 30 0.314159 37699 1256.633333
24 99.490346 32 0.321639 38596 1206.125000