Experimental content

• Toconvert a head measurement using a manometer to an equivalent pressurereading
• To demonstrate the use of a static pressure reading to determine tunnel air velocity
• Toconvert head andpressure readings to alternativeengineering units
• To demonstrate the difference between Static pressure, Dynamic pressure and Total pressure and how Dynamic pressure can be used to determine air velocity
• Toshowhowvelocityvariesinthetestsectionbecauseofthevelocityprofile
• To investigate the variation in Static Head resulting from a change in cross-sectional area
• To investigate the Bernoulli equation
• The visualisation of flow around a bluff body at different velocities
• The measurement of pressure distribution around a circular cylinder at different velocities
• Comparison of drag for shapes of equal equatorial diameter
• Visualisation of flow around different body shapes
• Measurement of the wake profile behind different shapes
• To investigate the pressure distribution around a symmetrical aerofoil at different angles
• To investigate the pressure distribution across the wake behind the wing
• To measure the depth of the boundary layer on smooth and rough flat plates
• To evaluate models or instruments of the students own design and/or manufacture

TheC15-10isacomputercontrolledcompactwindtunneldesigned forbenchtopoperation.Airisdrawnthroughtheworkingsectionby avariablespeedfanatthedischargeendofthetunnelprovidingup to34m/sairvelocity.

A honeycomb flow straightener is incorporated at the inlet, anda9:4:1contractionratiowhichensuresauniformairflow through the workingsection.

The working sectionisfabricatedfrom clear acrylictoprovide optimum visibilityofthemodelsandappropriatemodelconnectionpointsareincludedinthesidewallandroofoftheworkingsectiontoprovideeaseofuse.

The wind tunnel is supplied as standard with an in-depth software interfaceprovidingcontrolofthefanspeedandadditionallydisplay importantparameterssuchasstaticpressureandairvelocity.

The Armfield C15-10 can be optionally supplied with two variants of manometrybanks,a13tubewatermanometerusedtosimultaneouslydisplaydifferentialpressureorasixteenchannelelectronicmanometer allowingdirectintegrationintothesuppliedsoftware.

The wind tunnel can be supplied with a range of optional accessories includingdragbodies,liftbodies,pressuredistribution,boundarylayers studiesandmeasuringinstruments.

The optional models are mounted through a circular hatch using quick releaseclamps(120mmdiameter).Theplacementoftheoptionalmodels hasbeendesignedtominimisethedisturbancetoairflowandreduction in flow rate, whilst incorporating an angular scale allowing the model to bemanuallyrotatedtoknownangles.

The working section incorporates an innovative technique for flow visualisationaroundanyoftheoptionalmodelsavoidingtheneedfor eithersmokeordryice.Alightweighttwinefollowstheflowcontour aroundthemodelandshowsifandwhereboundarylayerseparation (breakaway)occurs.