Curved settling fronts within a rarefaction fan
= Curved settling fronts within a rarefaction fan
{title2=$z_u,z_d$}
For upper concentration $a$, lower concentration $b<a$ and $L=H-z_m$, define $A=aL$ and $D=(1-b)z_m$. Once inside the <settling rarefaction fan>, clearing and deposition <shocks> obey $z_u=z_m-u_st+2\sqrt{u_sAt}$ and $z_d=z_m+u_st-2\sqrt{u_sDt}$. These curves apply only while their neighboring concentration remains within the fan.