- #1
Niles
- 1,866
- 0
Hi
In my lecture notes we making some calculations and all terms [itex]\mathcal O(M^3)[/itex] are to be thrown away. Here M is the Mach number. Now, there is the expression (u denotes the velocity):
[tex]
uu\partial_t \rho \approx \rho_0 uu\nabla u
[/tex]
which in my notes are thrown away because they claim it is [itex]\mathcal O(M^3)[/itex]. But is it really true, I mean the derivative of u will not necessarily be on the same order as Ma, right?
In my lecture notes we making some calculations and all terms [itex]\mathcal O(M^3)[/itex] are to be thrown away. Here M is the Mach number. Now, there is the expression (u denotes the velocity):
[tex]
uu\partial_t \rho \approx \rho_0 uu\nabla u
[/tex]
which in my notes are thrown away because they claim it is [itex]\mathcal O(M^3)[/itex]. But is it really true, I mean the derivative of u will not necessarily be on the same order as Ma, right?