Mechanical Engineering - Theses

Permanent URI for this collection

Now showing 1 - 1 of 1

Instabilities of canopy flows

Mangalasinghe, Joel ( 2018)

Canopy flow is theoretically studied using three approaches from the literature that use empirically obtained mean flows. The first approach neglects the presence of the canopy and studies the stability of the mean flow. The second approach adds a canopy drag source term to the models in the first approach. The third approach treats the canopy as a porous medium by solving Darcy’s equation within the canopy, solving Rayleigh’s equation outside the canopy and coupling these solutions at the region the canopy loses its influence on the mean flow. The resulting dispersion relations show that the drag source term approach performs worse than when neglecting canopy drag, if the results are compared with experimental correlations. The dispersion relations also show that the porous medium approach is the best predictor of the dominant wavenumber. The perturbations in the vertical and streamwise directions as well as the vertical-streamwise perturbation correlations are obtained analytically and numerically. A PIV experiment currently in progress is aimed to verify the relevant model that agrees with experimental perturbation results or improve the canopy drag models currently in use.