#  Multi-light Sheet, Consecutive Overlapping Particle Image Velocimetry 

 



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Experimental investigation of problems of fluid-solid interactions, involving difference air-/waterborne vehicles require access to both boundary layers and the far-field flow around the body. However, a conventional particle image velocimetry measurement is either restricted to low resolution access to the entire flow field, or a high resolution access to a limited portion of the body. In addition, access to the surreounding of opaque and non-trasparent samples will always be limited by shadow areas.

To respond to this challange, we have developed a multi-light sheet strategy to access the flow field all around an opque body. For slender samples, we use double-light sheet illumination strategy to access both side of a sample.

   ![PIV_of_BL](/sites/g/files/omnuum9036/files/styles/hwp_1_1__960x960_scale/public/raayailab/files/fu_raaayai_graphical_abstract.png?itok=tmTr4AMf) 

 

To access the details of larger bodies and hard-to-reach areas inside arrays of obstrcutive objects we use a quad-sheet strategy to illuminate the details of the flow.

   ![Quad-sheet PIV](/sites/g/files/omnuum9036/files/styles/hwp_1_1__960x960_scale/public/raayailab/files/quad_sheet_website.png?itok=bQ4Iepqh) 

 

To have high resolution access to the flow details in both near and far-field, we perform experiments at high-magnification and repeat the experiments in consecutive-overlapping steps to cover a large area of interest, larger than the field-of-view of the camera. We use a Computer Numiercally Controlled rail to control the location of the camera and based of that location we are able to stitch the results back together to get the full view.

   ![Consecutive_overlap_gif](/sites/g/files/omnuum9036/files/styles/hwp_1_1__960x960_scale/public/raayailab/files/consecutive_overlaps.gif?itok=HmJRSouy) 

 

More details on the technique are available at:

- Shuangjiu Fu, Prasoon Suchandra, and Shabnam Raayai-Ardakani. “[Multi-sheet illumination and consecutive overlapping 2D-2C PIV acquisition for enhanced access to boundary layer flows around obstructive opaque objects.](/publications/multi-sheet-illumination-and-consecutive-overlapping-2d-2c-piv-acquisition)” In *15th International Symposium on Particle Image Velocimetry*. San Diego, CA: San Diego State University, **2023**.
- Shuangjiu Fu and Shabnam Raayai-Ardakani. “[Double-light-sheet, Consecutive-overlapping Particle Image Velocimetry for the Study of Boundary Layers past Opaque Objects](/publications/double-light-sheet-consecutive-overlapping-particle-image-velocimetry-study)” *Experiments in Fluids*, **2023**, 64(11):182.