Hi, all!

I’m having a hard time with the Chapman-Enskog analysis, at the point where you use the Euler Equations to rewrite time derivatives as spatial derivatives. In particular, I am reading Ladd’s 1994 Paper, where in Eq. (2.27) the time derivative needs to be eliminated from the following expression

I cannot seem to achieve this.

Similarly, Latt’s Thesis deals with the same term [quote=Latt]

d[sub]t[/sub] ( rho u u ),

[/quote]

in Eq. (2.64) on page 25 and somehow eliminates the time derivative.

Again, I cannot see why this equation holds.