Mathematical modelling.

<p>(a-c) Streamlines for the three flow fields observed in the reference case. By controlling the rate of airflow passing through the parachute, the permeability greatly influences the flow dynamics in the wake region. (d-f) The stream-wise component of the velocity vector is reported for the three case scenarios in 3D computations. The cone is represented in black, and the airflow moves from left to right. Case A—An unsteady vortex flow, for <i>K</i> = 1.0 x 10^–9 m², is shown at three time steps. The vortex shedding phenomenon is clearly visible (a, d); Case B—A steady vortex flow for two distinct time-steps (b, e). The negative values for the stream-wise velocity component just downstream the body (blue region) represent the recirculation area; Case C—Laminar shear flow for <i>K</i> = 6.0 x 10^–9 m² (c, f).