Hazel model
= Hazel model
{c}
The <Hazel model> is a smooth stratified <shear flow> whose base <velocity> has a hyperbolic-tangent profile and whose squared <buoyancy frequency> has a hyperbolic-secant-squared profile. The equal-width nondimensional example is $U=\tanh z$ and $N^2=J\operatorname{sech}^2z$. For $J\geq0$, its <gradient Richardson number> is $J\cosh^2z$, with minimum $J$.