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1answer
46 views

The solution to the non-linear convection equation

The non-linear convection equation $$u_{t} +uu_{x}=0$$ admits implicit solutions of the form $$u=f(x-ut).$$ How does one interpret this solution intuitively? Is there an example of a solution of this ...
1
vote
1answer
28 views

Formation of patterns in instabilities according to the wavelength of instability

Do the wavelengths of the instability have an influence on the type of patterns that we are going to get? Meaning for example in 2D, if the unstable wavelengths are small with respect to the size of ...
1
vote
1answer
85 views

Question about Strange Attractors

I'm reading the book Chaos by James Gleick and came upon a certain excerpt in the chapter 'Strange Attractors'. I'm having a hard time understanding it (the merging of two surfaces part, in particular)...
4
votes
1answer
519 views

Nonlinear waves equations derivation from Navier-Stokes

In my professor's lecture notes, I came across the next approach of studying non-linear waves in fluids. So we have compressible Navier-Stokes and continuity equation in 1D and we assume adiabatic ...
7
votes
1answer
90 views

How to popularly describe typical features of a “non-linear system”

To quote Physics.SE tag definition: The term non-linear or nonlinear has several definitions but is generally used to describe a system that cannot be approximated by a superposition principle or ...
33
votes
3answers
5k views

Why can't the Navier Stokes equations be derived from first principle physics?

At the 109th UCLA Faculty Research lecture, Seth Putterman gave a talk on Sonoluminescence. During the lecture he emphasized that "The Navier Stokes equations cannot be derived from first principles [...
11
votes
2answers
2k views

Explanation of the waves on the water planet in the movie Interstellar?

We will ignore some of the more obvious issues with the movie and assume all other things are consistent to have fun with some of these questions. Simple [hopefully] Pre-questions: 1) If the water ...
1
vote
1answer
685 views

Can I use Runge-Kutta to solve these equations?

Edit: I'm going to give some more background and derivation to show how I got to these equations. I am basically following the derivation that is found in the appendix of the following paper: R.M. ...
5
votes
2answers
1k views

Viscous Burgers equation physical meaning

The viscous Burgers' equation: $$ q_{t}+q\:q_{x}~=~\nu\:q_{xx}, \mbox{ where } \:\:\nu >0, $$ combines the nonlinear propagation of $q(x,t)$ and the diffusion. What is this equation for? (in ...
4
votes
1answer
2k views

Non-linear waves and shock formation

In the cases of non-linear acoustics, why is shock formation unlikely when the dispersion is strong when compared to the non-linearity of the wave?
5
votes
1answer
675 views

Shock Rarefaction Interaction

I am interested to see/know if there exist analytical solutions for shock/rarefaction interaction. A rarefaction wave can catch up to a shock wave from behind. The shock will decay and the motion ...