Figure 3
From: Numerical modeling of the wind flow over a transverse dune
Calculation of the average turbulent wind flow over the longitudinal slice of the transverse dune.
The calculation is performed for different values of wind shear velocity u*. From top to bottom, the values of u* used in the calculations are 0.1 m/s, 0.5 m/s and 1.2 m/s. The dune has height H = 3.26 m at the brink. Colors indicate mass flux per unit time (q), associated with each streamline, in units of kg/s, whereas the value of q increases from blue to red. The separating streamline is denoted by the continuous, thick line in each figure. The point where the separation streamline touches the ground is the flow reattachment point (xr), while the horizontal distance from the dune's brink (which is at position xb) to xr gives the reattachment length (l) associated with the given value of u*. The mass flow along the recirculating streamlines inside the separation bubble is in the clockwise direction, as indicated by the black arrows in the plot corresponding to u* = 0.1 m/s (top). The mass flow along all streamlines above the separating streamline is in the forward direction.
