Experimental and numerical investigation of the wake flow of a human-shaped manikin: Experiments by PIV and simulations by CFD

High-quality measurements of the flow structures induced by human movements are important for analyzing indoor air quality. This study measures the longitudinal and cross-sectional velocity and vortex fields behind the moving body, and investigates the effect of movement and body-shape on a wake flow structure. Experiments were conducted in a small-scale chamber with a moving human-shaped manikin, measured by the particle image velocimetry technique. The dynamic changes of the movement-induced wake flow were compared both in different times and movement stages. A strong downward airflow and an upward vortex were observed following the moving body. The measurements also revealed symmetric downward and expansive vortices in the wake flow. During the movement, a longitudinal recirculation region can be predicted around the manikin. Compared with a moving cylinder, this study shows that the specific shape of the legs exerts an obvious impact on the flow behind the lower limbs. In particular, a horizontal flow was observed penetrating from between the legs, with a velocity of 0.5 m/s, which was equal to the moving speed of the manikin. Meanwhile, a computational fluid dynamic model was also employed to simulate the unsteady instantaneous flow affected by the human movement. The numerical results can reveal different stages of the wake generation, development, and decay in detail during the movement. By quantitatively comparing with the experimental data, the LES method has rendered a good alignment with the experimental result, not only in the velocity magnitude value but also in fluctuating quantity.