Abstract: A simple PIV device is adopted to measure the velocity field of flow around a cylinder when the inlet velocity is 14.3 cm/s, and the pressure field is reconstructed by finite volume method and direct integral method. The error of velocity field measurement by simple PIV is analyzed by referring to the results of Fluent simulation, and the error of pressure field reconstruction by different algorithms based on Fluent-simulated velocity field and PIV-measured velocity field is also analyzed by comparing to the result of Fluent simulation. Results demonstrated that in the simple PIV system, camera could reduce the error of velocity field measurement by adopting suitable spatial resolution and time resolution. When given the first boundary condition on the basis of Fluent-simulated data, the error of pressure field reconstruction by finite volume method is smaller than that by direct integral method, with the root mean square error reaching 1.73% and 8.99%, respectively; on the basis of PIV-measured data, the reconstruction error by finite volume method is greater than that by direct integral method, with the root mean square error amounting to 26.58% and 12.72%, respectively. In conclusion, reducing the error of velocity field and setting up accurate boundary conditions could improve the reconstruction accuracy of pressure field. The analysis result is aimed at exploring the reconstruction method for transient pressure field of fluid through low-cost PIV device, so as to reduce the cost of measuring pressure field from PIV.

Key words: reconstructed pressure field, PIV, velocity field, finite volume method, direct integral method