CWT tank

  • IMT technician and apprentice working on a project in the CWT-lab. Photo: Kai T. Dragland / NTNU

  • CTW tank technicians and apprentice preparing a test. Photo: Kai T. Dragland/NTNU

  • Overall view of the CWT tank. Photo: Kai T. Dragland/ NTNU

  • Trond Innset and Ole Erik Vinje working in the CWT-lab. Photo: Kai T. Dragland

Circulating water tunnel (CWT)

Circulating water tunnel (CWT)

The circulating water tunnel is the first test tank at the Department of Marine Technology (IMT) where the use of optical flow measurement systems (like PIV or LDV) was considered right from the planning phase.

Hence, the tank comprises an entirely transparent, rectangular test section that can be observed from downstream as well. It was manufactured by Engineering Laboratory Design US  and installed in the spring of 2010. For inquiries contact Emil Bratlie.

The lab is operated by IMT in co-operation with SINTEF Ocean.

It is being used for fluid flow demonstrations, as a student laboratory and in PhD research projects. Special attention is paid to projects integrating EFD and CFD. For teaching purposes, there is a flow visualization kit installed and several student workplaces are prepared.



  •  All over size (L x W x H): 9.10 x 3.00 x 2.10 m
  •  Test section size: 2.50 x 0.61 x 0.61 m
  •  Low turbulence level of 1% of free stream velocity
  •  Velocity profile outside boundary layers +/- 1% of mean velocity
  •  Flow speed from 0.03 to 1 m/s
  •  Operation with free surface or closed lid.
  •  The ambient pressure can't be lowered – it is not a cavitation tunnel


Photo: Dye visualization of the Vortex Street behind a circular cylinder.