Table 1.
L, cm | L/λ | Pitch angle, ° | A, cm | B, cm2 | D, cm3 | ɛmax, % | f, sec−1 |
---|---|---|---|---|---|---|---|
5.2 | 5 | 55 | 0.67 | 0.032 | 0.076 | 0.48 | 89 |
7.8 | 5 | 39 | 0.71 | 0.038 | 0.06 | 0.78 | 85 |
9.4 | 5 | 20 | 0.74 | 0.018 | 0.031 | 0.34 | 188 |
3.1 | 3 | 55 | 0.48 | 0.023 | 0.053 | 0.46 | 62 |
7.5 | 7 | 56 | 0.91 | 0.053 | 0.13 | 0.54 | 100 |
[Test helices (Fig. 5) of length L, wavelength λ, and specified pitch angle were allowed to sink under their own weight in silicon oil (η ≈ 1,000 g⋅cm−1⋅sec−1). The sinking speeds and speeds of rotation were measured, and A, B, and D were determined through Eqs. 20a and 21; their values have been divided by 6πη, so that their dimensions are cm, cm2, and cm3, respectively. ɛmax is the maximal propulsion efficiency expected when the test helix is connected to a sphere of radius A (Eq. 22). f is the motor speed required to drive that sphere 20A⋅sec−1 (Eq. 19).]