diff --git a/300s School/ME 2016 - Nonlinear Dynamical Systems 1/2024-11-18 Volume Contraction.md b/300s School/ME 2016 - Nonlinear Dynamical Systems 1/2024-11-18 Volume Contraction.md new file mode 100644 index 000000000..a791910d9 --- /dev/null +++ b/300s School/ME 2016 - Nonlinear Dynamical Systems 1/2024-11-18 Volume Contraction.md @@ -0,0 +1,15 @@ +Lorenz system is dissapative. This means: +- Volume in phase space contracts with flow? +This introduces some questions... How do volumes evolve? + +Suppose a surface $S(t)$ encloses volume $V(t)$, with normal vectors pointing away from the surface ($\vec{n}$). + +A trajectory starts on S. let them evolve for $dt$. With a flux vector $\vec{f}$, we have +- $\vec f \cdot \vec n$ - normal, outward component of velocity +In $dt$ time, $dA$ sweeps out a volume. + +Volume: $(\vec f \cdot \vec n dt)dA$ +$$V(t+dt) = V(t) + \int_S (\vec f \cdot \vec n dt)dA $$ +$$\dot{V} = \int_S (\vec f \cdot \vec n)dA $$ +Now we can apply the divergence theorem: +$$\dot{V} = \int_V (\nabla \cdot \vec f )dV $$ diff --git a/300s School/ME 2016 - Nonlinear Dynamical Systems 1/2024-11-18.md b/300s School/ME 2016 - Nonlinear Dynamical Systems 1/2024-11-18.md deleted file mode 100644 index e69de29bb..000000000