Multiple-pulse PIV: Numerical evaluation and experimental validation

Multiple-pulse PIV: Numerical evaluation and experimental validation

Ding, L.
Discetti, S.
Adrian, R.J.
Gogineni, S.

2013-07-03

Many conventional experimental methods in fluid mechanics, such as LDV and HWA, are not able to measure simultaneous acceleration fields directly. Double-pulse PIV is extended to the multiple-pulse PIV enabling people to directly extract acceleration fields as well as to achieve better accuracy in the velocity measurement [13]. We evaluate the performances of triple-pulse PIV and quadruple-pulse PIV based on PTV simulations. By investigating various flow conditions, optimizations are globally achieved to minimize the error in velocity and acceleration measurements for both triple-pulse and quadruple-pulse PIV. Compared to that with uneven time spacing, triple-pulse PIV with even time spacing yields better spatial resolution in velocity measurement. Moreover, quadruple-pulse PIV significantly reduces the error in both velocity and acceleration measurement relative to triple-pulse PIV. Experimental validation of the acceleration measurement from triple-pulse PIV is conducted by measuring the mean centerline acceleration profile of a round impinging air jet. A custom 8-pulse laser system in combination with an ultra high-speed 4-channel camera are utilized to well satisfy the requirements of multiple-pulse PIV. Conventional double-pulse PIV, together with the polynomial curve fitting, are used to obtain the ground truth for the mean centerline acceleration profile. The comparison between the ground truth and acceleration measurements by triple-pulse PIV shows a good agreement with the maximum error being 10% of the full scale acceleration. Several potential error sources are also discussed to provide the direction of making improvements in the following stage.

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Conference proceedings

conference paper

(c) 2013 Ding, L.; Discetti, S.; Adrian, R.J.; Gogineni, S.