This is an ongoing project in BATL since Spring 2019. The aim of this experiment is to study compressible turbulent jets at high Reynolds numbers. I have been measuring profiles of a turbulent jet at various Reynolds and Mach numbers. These parameters are varied by changing the pressure and gas density within a fixed volume pressure vessel.
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After designing and setting up the test fixture, I started measuring jet profiles with a pitot tube to verify the setup was providing Gaussian velocity jet profiles in air at standard conditions. Initially the velocity profiles were skewed and asymmetric as shown below, but it was suspected that the ducted fan generating the jet caused significant gas heating effects. An ongoing project is a cooling system for the fan to reduce this.
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With this in mind, I have taken more profiles attempting to mitigate this by estimating the time taken to cool sufficiently to reduce skew. This has been a good short term solution to the heating problem, but means experiments are slow and can take up to 10 hours to gather data.
Preliminary profiles normalized have been promising, verifying results found in literature. With the experimental setup producing good results, my next project will be to very the Mach numbers to observe the jet behaviour, and whether it changes once turbulence becomes compressible. For more details on the experiment and comparisons to literature, check out my report from this Spring.
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After designing and setting up the test fixture, I started measuring jet profiles with a pitot tube to verify the setup was providing Gaussian velocity jet profiles in air at standard conditions. Initially the velocity profiles were skewed and asymmetric as shown below, but it was suspected that the ducted fan generating the jet caused significant gas heating effects. An ongoing project is a cooling system for the fan to reduce this.
With this in mind, I have taken more profiles attempting to mitigate this by estimating the time taken to cool sufficiently to reduce skew. This has been a good short term solution to the heating problem, but means experiments are slow and can take up to 10 hours to gather data.
Preliminary profiles normalized have been promising, verifying results found in literature. With the experimental setup producing good results, my next project will be to very the Mach numbers to observe the jet behaviour, and whether it changes once turbulence becomes compressible. For more details on the experiment and comparisons to literature, check out my report from this Spring.
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