E. Özahi and M. Ö. Çarpınlıoğlu
3rd International Conference on Fluid Mechanics and Heat and Mass Transfer (Fluids-Heat'12), ISBN 978-1-61804-078-7, pp.39-44, Vouliagmeni Beach, March 7-9, Athens, Greece,
Publication year: 2012


An experimental study conducted on pulsatile pressure and velocity measurements inside a sinusoidal air flow medium is presented. Controlled oscillation frequency, f and velocity amplitude ratio, A1 are satisfied via so called mass flow control (MFC) unit. Velocity and pressure data through the signals of hotwire anemometer and pressure transmitters are acquired and processed via the data acquisition system which is composed of hotwire anemometer and probe, pressure transmitters, in connection with an IOtech Daq3001 USB board installed. The operation of the measurement chain, signal-data acquisition and data processing is handled through the devised software program named as Time Dependent Flow Control.vi (TDFC.vi) in LabView 2009SP1® environment.
In this paper, the details of the software programming utilized for the oscillation generation, control and relevant data acquisition in the experimental ranges of time-averaged Reynolds number, Reta of 1019±35≤Reta≤4817±164, oscillating Reynolds number, Reas of 107±4≤Reas≤4261±145, velocity amplitude ratio, A1 of 0.05±0.0017≤A1≤0.96±0.03 and Womersley number, √ω of 2.72≤√ω≤32.21 are presented. Instantaneous wall shear stress, τω(t) is evaluated using the solution of time-dependent momentum integral equation. Instantaneous friction factor, λu(t), time-averaged friction factor, λu,ta and laminar quasi-steady friction factor, λqL(t)
are calculated in the devised program, TDFC.vi.

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