Much of the work carried out by the group requires significant computational power, which is obtained from Multi-CPU clusters. Multi-CPU clusters allow 'parallel' codes to be run, i.e. large problems split and run over several CPUs simultaneously, but also allow scalar codes to be run with multiple data sets simultaneously, i.e. a 'scalar farm'. The group uses two main computational resources:
- Kittyhawk is the primary code development machine for the group. It comprises 120 2.2GHz Opteron CPUs running as a Linux cluster. The machine contains 60 dual processor nodes with 4Gbytes RAM each, and eight dual processor nodes with 8GBytes RAM each, all linked via Gbit/second ethernet switches.
- Bluecrystal, the University of Bristol's main supercomputing resource comprising 3400 cores and Infiniband interconnects producing 28.4 TFLOPS of processing power. More details on Bluecrystal are available from the Advanced Computing Research Centre homepage.
This consists of a very quiet closed-circuit wind tunnel and a large anechoic chamber. The Wind tunnel is powered by a 50kW centrifugal fan and is equipped with a series of large silencers to reduce the fan noise in the ductwork. The wind tunnel is equipped with a 40kW water cooled chiller, enabling continuous testing at a set temperature, between 18o to 25 o. The anechoic chamber is approximately 7m x 4.5m x 3.5m and is fully anechoic down to 250Hz. Several contraction nozzles, with different aspect- and contraction-ratios have been made for measurement of noise from different aero-components, such as aerofoils, bluff bodies, boundary layer, etc. The working section of the wind tunnel is equipped with Dantec hotwire CTA system, 2D PIV, source location microphone array (48 microphones) and an array of GRAS and B&K free-field microphones. Two National Instrument DAQ are used in the aeroacoustics facility, enabling simultaneous data collection of up to 84 channels. The facility can also be turned into a jet noise facility with flight stream. The jet noise apparatus is connected to the main pressurized air system, with air supply of 460 lit/sec at 7bar. The jet noise measurement can be carried out in the presence of flight stream by changing the contraction nozzle to a circular nozzle. Tests can be done for jet flows of up to Mach 0.9 and with flight-stream of 120 knots (61 m/s).
Jet noise facility
The jet noise facility is ideal for fundamental and industrial jet noise, jet installation effects and flow instability studies. The air supplied by three separate compressors, providing over 500 litre per second of compressed air, enables to obtain a jet flow at Mach numbers in the range between 0.1 and 0.95, using a canonical nozzle with an exit diameter of 1.5”. The jet is placed in the UoB anechoic chamber and its flow rate can be controlled using an electronic flow regulator. A large 3-turn labyrinth silencer of dimension 0.8m x 0.8m x 1.2m is used to eliminate the noise from the compressors. The jet test-rig is made such that the nozzle can be changed readily for studies involving different nozzle configurations. The facility also has the capability to carry out jet noise studies in the presence of flight stream. The facility can deliver a flight stream velocity of 120 knots (61 m/s), with a circular flight-stream nozzle 60cm of diameter. The anechoic chamber is equipped with 50 free-field microphones located 2m (50 diameters) from the jet nozzle, covering polar angles from 30 degrees to 120 degrees. A set of powerful loudspeakers are also placed in the silencer, which can be used to trigger flow instabilities in the jet shear layer and in the potential core.
Wind tunnel laboratory
- Large Low Speed Wind Tunnel: 2.1 m x 1.5 m octagonal section; maximum speed 60 m/s; main uses: aerodynamics of aircraft, missiles, propellors, rotors and cars. Also, return section, 5.5 m x 2.6 m, maximum speed 12 m/s; main uses: rotor studies.
- Low Turbulence Wind Tunnel: 0.8 m x 0.6 m octagonal section; maximum speed 100 m/s; turbulence level 0.05%; main uses: fundamental fluid mechanics and aerodynamics.
- Open Jet Wind Tunnel: 1.1 m diameter; maximum speed 40m/s; main uses: aerofoil characteristics, vibration and oscillation studies.
- Open Return Low Speed Tunnels (2): 0.6 m x 0.6 m working section; maximum speed approx. 35 m/s; main uses: teaching and student projects.
- DANTEC 3D Laser Doppler Anemometer: Fibre-optic linked 5W argon-ion laser, 600 mm or 1600 mm focal length; high precision 3-axis traverse; processing by 3 Burst Spectrum Analysers.
Hele-Shaw (hydraulics) laboratory
The Hele-Shaw laboratory is a new facility specialising in different areas of fluid mechanics teaching and research. It houses the University's capability in low viscosity liquids and multi-phase interactions between liquid and gas. The space is open-plan to jointly serve the needs of teaching and research across the Faculty.
More information: bristol.ac.uk/heleshawlab
The University has invested £12 million in its Advanced Computing facilities since 2006, making it one of the country’s leading centres. Bristol hosts one of the fastest and most advanced supercomputing facilities in the UK, capable of over 200 trillion calculations per second.
High speed jet noise facility
Did you know?
The Faculty of Engineering has one of the best university wind-tunnel laboratories in the country for aerodynamic testing and was even used to test the aerodynamics of Wimbledon No. 1 Court!