Signature wake of mangrove roots models. Soap film experiment flow visualization snapshot of von Kármán vortex street behind arrays of nine cylinders for an impermeable and a porous patch, representing mangrove roots. We observed two regions behind the patch associated with small-scale turbulence (as shown in fames) of individual cylinders and formation of 2S mode wake. λ is the wavelength of the vortex street and gets smaller by increasing the porosity.