Time-averaged velocity and scalar fields of the flow over and around a group of cylinders: a model experiment for canopy flows

We conduct a well-controlled model experiment for wide variety of canopy flows. Examples these include engineering flows such as wind flow, dispersion scalars through and over urban areas, the convective heat transfer in many exchangers, well natural canopies terrestrial or aquatic vegetation. aim to shed light on fundamental flow transport phenomena common applications. Specifically, characteristics mean scalar concentration turbulent boundary layer impinging canopy, which comprises cluster tall obstacles (this can also be interpreted porous obstruction). The is created with group cylinders diameter $d$ height $h$ arranged circular patch $D$ . solidity patch/obstruction defined by $\phi$ (the total planar area covered cylinders), systematically varied ( $0.098 \leq \phi 1$ ) increasing number $N_c$ ). A point source placed at ground level upstream its around examined. Time-averaged velocity fields, obtained from simultaneous particle image velocimetry-planar laser-induced fluorescence (PIV-PLIF) measurements, reveal that wake above patches are heavily influenced In particular, we observe horizontal vertical extent downstream decreases increases , respectively. Here, recirculation bubble shifted closer trailing edge (TE) increases, limiting convecting downstream, decreasing virtually ‘extending’ streamwise direction. As forms TE, bleeding hence where appear ‘extend’ vertically towards freestream.