For uniform laminar flow(in the $x$-direction) past a flat plate at high Reynolds number, the local boundary layer thickness ($\delta$) varies with the distance along the plate $(x)$ as
- $\delta\propto x^{1/4}$
- $\delta\propto x^{1/3}$
- $\delta\propto x^{1/2}$
- $\delta\propto x$