Oral Exam: On Radial Symmetry of Uniformly Rotating/ Stationary Solutions to 2D Euler Equation

Series
Other Talks
Time
Tuesday, April 23, 2019 - 3:00pm for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Jaemin Park – Georgia Institute of Technology – jpark776@gatech.eduhttp://people.math.gatech.edu/~jpark776/
Organizer
Jaemin Park

We study whether all stationary solutions of 2D Euler equation must be radially symmetric, if the vorticity is compactly supported or has some decay at infinity. Our main results are the following:

(1) On the one hand, we are able to show that for any non-negative smooth stationary vorticity  that is compactly supported (or has certain decay as |x|->infty), it must be radially symmetric up to a translation. 

(2) On the other hand, if we allow vorticity to change sign, then by applying bifurcation arguments to sign-changing radial patches, we are able to show that there exists a compactly-supported, sign-changing smooth stationary vorticity that is non-radial.

We have also obtained some symmetry results for uniformly-rotating solutions for 2D Euler equation, as well as stationary/rotating solutions for the SQG equation. The symmetry results are mainly obtained by calculus of variations and elliptic equation techniques. This is a joint work with Javier Gomez-Serrano, Jia Shi and Yao Yao.