Quiet Wind Tunnel
Parent Body: Defence Evaluation and Research Agency (DERA), Haslar, Gosport, Hampshire, PO12 2AG

Principal Functions
Propulsor noise, flow and turbulence studies.

Subsidiary Functions
Flow visualisation, fan noise measurements.

General Details
The Quiet Wind Tunnel is an open circuit, open jet wind tunnel used for noise, flow and turbulence studies, and is particularly directed towards the reduction of noise levels of hydrodynamic origin radiated from submarines. Noise from propulsors is particularly important, and is generated by a number of distinct mechanisms, some of which are more easily studied in a wind tunnel rather than the equivalent hydrodynamic facilities, despite the difficulties associated with hydrodynamic and acoustic scaling.

Specification
The structure is made from standard silencing panels and extensive use is made of anti–vibration mountings and couplings to minimise noise transmission. The working chamber itself is further isolated from ambient noise by a muffler and sound absorbent linings at the inlet and from fan noise by fan inlet and outlet silencers, and by the plenum chamber and its lining. The effective dimensions of the working chamber are 3m × 3m × 2m high. Air is drawn through it at speeds of up to 50m/s, and with longitudinal turbulence level of 0.2% when no model is present. It can be considered to be anechoic at frequencies above 400Hz.

Special Features
Support staff for the operation of the facility are provided. Sensors can be mounted on a computer controlled robot. Pitot-static, hot-wire and laser Doppler systems are available for the measurement of mean flow velocity and turbulence.

Availability
The facility is available to other bodies in both the private and public sector. There are no restrictions on the type of body that can apply to use the facility. The advance notice required when requesting time on the facility is three months. Time on the facility is allocated first on peer review for the academic programme, then vacant slots are offered for repayment work.

Charging Basis
Charging rates are subject to negotiation.

Site Access
The site has ready access for vehicles and local accommodation is available for the hirer’s staff.

Contact Information
Ian Grant, Commercial Manager
Centre for Marine Technology
Building 58, Room 114A
DERA Haslar
Haslar Road
Gosport
Hants, PO12 2AG
Telephone: 023 9233 5130      Fax: 023 9233 5012
E-mail:  idgrant@dera.gov.uk