DIGITAL VECTOR IMAGE-PROCESSING OF LID-DRIVEN ROTATING CAVITY FLOW

A flow visualization method entitled Digital Vector Velocimetry (DVV) method is introduced to extract the flow field quantitatively from par ticle images. This methodis applied to a lid-driven rotating cavity fl ow. In the DVV method, a time sequence of images are captured by a CCD (charge Coupled Device) video camera with each frame containing a sin gle-exposure image. All possible velocity vectors between two temporal ly successive images in the interrogating window are digitally constru cted on the digital vectorgram. The most probable velocity vector is i dentified as the velocity vector of the maximum intensity in the digit al vectorgram. The DVV system provides measurement with subpixel accur acy. The dynamic range of the velocity is expanded using feedback anal ysis that selects consistent velocity vectors.