Recent applications of STB and FlowFit - CUBE synthetic test case and large-scale impinging jet

Abstract

The novel Lagrangian particle tracking method Shake-The-Box (STB) has been applied to a synthetic turbulent channel flow test case based on projections of particles which follow the DNS simulated flow towards four cameras. A benchmark test for 3D particle reconstruction and velocity field estimation has been carried out between the partners at ONERA and DLR-AS-EXV on two step, four step and fully time resolved particle image series from virtual cameras. Furthermore, an experimental set-up for measuring the flow of a large scale turbulent impinging jet has been explained. The set-up consists of six PCO.Dimax high-speed cameras operating between 1 and 3.9 kHz frame rate together with pulsed LED arrays illuminating HFSB in the jet flow of maximal velocities up to 18 m/s. The STB measurement domain consists of a wall-bounded volume covering a stream- and spanwise area of 500 x 500 x 200 mm³. A comprehensive set of relatively dense Lagrangian track data was reconstructed from several time resolved sequences. The data enables an accurate and high resolution measurement of the velocity, acceleration and Reynolds stresses. Furthermore, an interpolation algorithm regularized by the incompressible NS-equation named FlowFit has been applied resulting in the corresponding time-resolved 3D velocity and acceleration vector and pressure field volumes on a regular grid using the time series of irregularly distributed Lagrangian track data. With the present data coherent structures and their pressure dynamics close to the wall will be investigated based on synchronous flush mounted microphone measurements.