Blade image velocimetry: development and uncertainty analysis

Abstract

This paper describes the development of a non-contact structural vibration measurement technique referred to as blade image velocimetry (BIV). The technique utilizes a commercially available single camera PIV system and, when used with PIV, can measure fluid and structure velocity simultaneously. The utility of this measurement technique was demonstrated on a flat plate undergoing flutter. The structural velocity measurements were experimentally demonstrated to be of comparable accuracy to standard PIV measurements. The theory relating the measurements obtained by BIV of the structure is presented. An uncertainty analysis was developed by considering two sources of error associated with the modal amplitude estimates. Through benchtop tests, it was found that these two sources of error predict the experimentally observed bias errors well.