RV Sarsia 15/75
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RV Sarsia (74SR) |
| Cruise identifier | 15/75 |
| Cruise period | 1975-05-27 — 1975-06-05 |
| Status | Completed |
| Port of departure | Plymouth, United Kingdom |
| Port of return | Plymouth, United Kingdom |
| Purpose | Research |
| Objectives | The main purpose of the cruise was to take measurements of the turbulence in the boundary layer close to the sea bed in areas of simple topography using electromagnetic flowmeters. In particular the intermittency in the turbulent momentum fluxes, the Reynold stresses, were to be examined at two levels in order to obtain data for a comparison with recently published laboratory work and for studies on sediment transport. Velocity profiles were also planned using an array for four rotor current meters and the bed shear stresses, calculated from the logarithmic profile using results averaged over one minute, would be compared with the Reynolds stress values. Additionally the turbulence data would be analysed for turbulent intensities, spectra, co-spectra and presented in the formats used by many other workers. An underwater television would be used for examining the water flow in the vicinity of the sensors, and to monitor changes in the form of the bed and sediment movement.
Experiments to measure the noise present near the sea bed in the frequency range of several kiloHertz to 400 kiloHertz were also to be carried out, as time permitted, to examine the contribution to the spectrum of the noise generated by the sediment when in motion. Based on previous work seven positions had been chosen within Start Bay, a known area of fine/medium uniform sand with low shell content. It was anticipated that the areas would be rippled and that some of them would have small dunes present. The sands were expected to be mobile under extreme conditions. |
| Chief scientist | Keith Dyer (Institute of Oceanographic Sciences Taunton) |
| Cruise report |  (0.78 MB) |
| Ocean/sea areas | |
| General | Irish Sea and St. George's Channel |
| Measurements | |
| Physical oceanography | |
| Current meters | Quantity: 4 |
| Other physical oceanographic measurements | Quantity: 2 Description: Electromagnetic current meters for turbulence measurements |
| Geology and geophysics | |
| Bottom photography | Quantity: 3 Description: TV-film of sea bed |
