The new Pressure from PIV software package meets the strong demand for direct extraction of full 3D and 2D pressure fields from PIV and Shake-the-Box (4D-PTV) data. With only a few clicks, Pressure from PIV together with LaVision’s DaVis 10 software retrieves and visualizes average pressure fields from all kinds of PIV and PTV velocity data either imported to or directly computed by DaVis. For time-resolved data, even the instantaneous pressure can be evaluated.
Commonly, pressure measurements are retrieved pointwise, for instance with pressure taps or Pitot tubes. Instrumentation of wind tunnel models with pressure sensors is time consuming, complex and expensive. In the European NIOPLEX project, several universities and LaVision joined forces to develop a non-intrusive, direct method for pressure retrieval in complete volumes. This project finally pinpointed practical ways for pressure calculation from PIV/PTV measurements.
LaVision’s ongoing inhouse developments use sophisticated mathematics. Today, all LaVision pressure solvers free the user from limitations on the shape of the test domain that are enforced by common pressure solvers. Furthermore, a new 4D pressure solver was developed for instantaneous pressure fields, which yields stable and reliable pressure results. The central idea of the 4D Pressure Solver is to utilize the temporal information enforcing temporal continuity. Also user-efforts to define boundary conditions are minimized.
The 4D pressure solver takes 4D spatio-temporal blocks into account. Each 4D block consists of multiple 3D domains and their Lagrangian connections in the time domain. User-defined boundary conditions are only required for the first time-step of the first 4D block. For the following 4D blocks, pressure results from previous blocks are transferred to the next 4D step. In this way, the temporal continuity is assured and unphysical fluctuations are avoided.