A cheap and rugged field PIV system

To date, there is a lack of turbulence data in natural aquatic systems. Adapting particle image velocimetry (PIV) to field use will provide such data. We present a new field PIV system optimized for high portability and low cost. This system was tested in the Huron River in Ann Arbor, MI, at various locations along the river. All measurement sites were close to shore (with depths of less than 1.5 m), and sampled a variety of environments, including bulrush marsh, pebble bank, boulder field, and woody debris. Turbulence metrics significant to aquatic biota were captured. Velocity was validated through comparison with an acoustic doppler velocimeter (ADV) and an electromagnetic flowmeter, and had an average 4.8% difference from these methods. Turbulence kinetic energy was validated through comparison with an ADV, and fell within one standard error. Vorticity, eddy size, and eddy circulation were validated at a field site by repeating measurements taken using a different field PIV system. Each of these data sets fell within the range of the validation measurements. This novel, low-cost, highly portable system provides accurate turbulence measurement, therefore offering an accessible method of acquiring meaningful field turbulence data for a wide range of users.