High-Speed 2D Flow Mapping via Image-FLDI

Image focused laser differential interferometry (I-FLDI) is developed via the introduction of a microlens array as the expander lens and the traditional use of Wollaston prisms in the FLDI setup. This new design allows for a 66x66 grid of beam pairs, creating a 2D visualization of the flow field, which is useful for imaging complex phenomena such as shock diamonds, turbulent boundary layer transitions, and shock wave boundary layer interactions. This work demonstrates how the FLDI system can be scaled to a vast number of points, creating high-resolution images. The grid is focused to a region of interest, providing numerous individual FLDI measurements simultaneously. The system may be shifted along an axis to capture the full test section, enabling a three-dimensional reconstruction of the flow. Future efforts to calibrate these points will enable I-FLDI as a quantitative measurement tool in addition to its imaging capabilities.