Applied/ACMS: Difference between revisions

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*'''When:''' Fridays at 2:25pm (except as otherwise indicated)
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)
*'''Where:''' 901 Van Vleck Hall
*'''Where:''' 901 Van Vleck Hall
*'''Organizers:''' [http://www.math.wisc.edu/~spagnolie Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]
*'''Organizers:''' [https://math.wisc.edu/staff/fabien-maurice/ Maurice Fabien], [https://people.math.wisc.edu/~rycroft/ Chris Rycroft], and [https://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie],
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+subscribe@g-groups.wisc.edu].


<br>
<br>  


== Spring 2018  ==
== '''Spring 2025''' ==
 
{| cellpadding="8"
{| cellpadding="8"
!align="left" | date
! align="left" |Date
!align="left" | speaker
! align="left" |Speaker
!align="left" | title
! align="left" |Title
!align="left" | host(s)
! align="left" |Host(s)
|-
|-
| Jan. 26
|Jan 31
|  
|[https://people.math.wisc.edu/~tgchandler/ Thomas Chandler] (UW)
|  
|[[#Chandler|TBA]]
|  
|
|-
|-
| Feb. 2 '''4pm'''
|Feb 7
|[https://scholar.harvard.edu/tfai Thomas Fai] (Harvard)
|[https://www.colorado.edu/aps/adrian-fraser Adrian Fraser] (Colorado)
|''[[Applied/ACMS/absS18#Thomas Fai (Harvard) | TBA]]''
|[[#Fraser|''Destabilization of transverse waves by periodic shear flows'']]
| Spagnolie
|Spagnolie
|-
|-
| Feb. 9
|Feb 14
|[https://sites.google.com/site/michaelherty/home Michael Herty] (RWTH-Aachen)
|TBA
|''[[Applied/ACMS/absS18#Michael Herty (RWTH-Aachen) | Opinion Formation Models and Mean field Games Techniques]]''
|
|Jin
|
|-
|-
| Feb. 16
|Feb 21
|TBA
|
|
|
|-
|Feb 28
|[https://nmboffi.github.io/ Nick Boffi] (CMU)
|[[#Boffi|TBA]]
|Li
|-
|Mar 7
|TBA
|
|
|
|
|-
|-
| Feb. 23
|Mar 14
|[https://people.ucsc.edu/~fmonard/ François Monard] (UC Santa Cruz)
|[https://lu.seas.harvard.edu/ Yue Lu] (Harvard) '''[Colloquium]'''
|''[[Applied/ACMS/absS18#François Monard (UC Santa Cruz) | TBA]]''
|[[#Lu|TBA]]
|Li
|Li
|-
|-
| ''' Wed, Feb. 28'''
|Mar 21
|[http://www.math.nus.edu.sg/~matyh/ Haizhao Yang] (National University of Singapore)
|[https://people.llnl.gov/vogman1 Genia Vogman] (LLNL)
|''[[Applied/ACMS/absS18#Haizhao Yang (National University of Singapore) | TBA]]''
|[[#Vogman|TBA]]
|Li
|Li
|-
|-
| Mar. 2
|Mar 28
|[http://wwwf.imperial.ac.uk/~ekeaveny/ Eric Keaveny] (Imperial College London)
|''Spring Break''
|''[[Applied/ACMS/absS18#Eric Keaveny (Imperial College London) | TBA]]''
|
|Spagnolie, Thiffeault
|
|-
|-
| Mar. 9
|Apr 4
|
|TBA
|
|
|
|
|-
|-
| Mar. 16, '''4pm'''
|Apr 11
|[https://math.dartmouth.edu/~annegelb/ Anne Gelb] (Dartmouth)
|[https://meche.mit.edu/people/faculty/pierrel@mit.edu Pierre Lermusiaux] (MIT)
|''[[Applied/ACMS/absS18#Anne Gelb (Dartmouth) | TBA]]''
|[[#Lermusiaux|TBA]]
|Li
|Chen
|-
|-
| Mar. 23
|Apr 18
|[https://panlab.weebly.com/ Wenxiao Pan] (UW)
|[https://www.math.uci.edu/~jxin/ Jack Xin] (UC Irvine) '''[Colloquium]'''
|''[[Applied/ACMS/absS18#Wenxiao Pan (UW) | TBA]]''
|[[#Xin|TBA]]
|Spagnolie
|
|-
| Mar. 30
|Spring break
|
|
|-
| '''Wed. Apr. 4'''
|[http://people.math.gatech.edu/~mtao8/ Molei Tao] (Georgia Tech)
|''[[Applied/ACMS/absS18#Molei Tao (Georgia Tech) | Explicit high-order symplectic integration of nonseparable Hamiltonians: algorithms and long time performance]]''
|Jin
|-
| Apr. 6
|[http://jfi.uchicago.edu/~william/ William Irvine] (U Chicago)
|''[[Applied/ACMS/absS18#William Irvine (U Chicago) | TBA]]''
|Spagnolie
|-
|-
| Apr. 13
|Apr 25
|tentative
|[https://www-users.cse.umn.edu/~bcockbur/ Bernardo Cockburn] (Minnesota)
|tba
|[[#Cockburn|''Transforming stabilization into spaces'']]
|Smith, Stechmann
| Stechmann, Fabien
|-
|-
| Apr. 20
|May 2
|
|[https://sylviaherbert.com/ Sylvia Herbert] (UCSD)
|
|[[#Herbert|TBA]]
|
|Chen
|-
| Apr. 27
|
|  
|  
|}
|}
==Abstracts==
<div id="Fraser">
====Adrian Fraser (Colorado)====
Title: Destabilization of transverse waves by periodic shear flows
Periodic shear flows have the peculiar property that they are unstable to large-scale, transverse perturbations, and that this instability proceeds via a negative-eddy-viscosity mechanism (Dubrulle & Frisch, 1991). In this talk, I will show an example where this property causes transverse waves to become linearly unstable: a sinusoidal shear flow in the presence of a uniform, streamwise magnetic field in the framework of incompressible MHD. This flow is unstable to a KH-like instability for sufficiently weak magnetic fields, and uniform magnetic fields permit transverse waves known as Alfvén waves. Under the right conditions, these Alfvén waves become unstable, presenting a separate branch of instability that persists for arbitrarily strong magnetic fields which otherwise suppress the KH-like instability. After characterizing these waves with the help of a simple asymptotic expansion, I will show that they drive soliton-like waves in nonlinear simulations. With time permitting, I will discuss other fluid systems where similar dynamics are or may be found, including stratified flows and plasma drift waves.
====Bernardo Cockburn (Minnesota)====
Title: Transforming stabilization into spaces
In the framework of finite element methods for ordinary differential equations, we consider the continuous Galerkin method (introduced in 72) and the discontinuous Galerkin method (introduced in 73/74). We uncover the fact that both methods discretize the time derivative in exactly the same form, and discuss a few of its consequences. We end by briefly describing our ongoing work on the extension of this result to some Galerkin methods for partial differential equations.
<div id="Bal"><div id="Portone"><div id="Damle"><div id="Sprague"><div id="Holmes-Cerfon"><div id="Sun"><div id="Maxian"><div id="Lavi">


== Archived semesters ==
== Archived semesters ==
*[[Applied/ACMS/Fall2024|Fall 2024]]
*[[Applied/ACMS/Spring2024|Spring 2024]]
*[[Applied/ACMS/Fall2023|Fall 2023]]
*[[Applied/ACMS/Spring2023|Spring 2023]]
*[[Applied/ACMS/Fall2022|Fall 2022]]
*[[Applied/ACMS/Spring2022|Spring 2022]]
*[[Applied/ACMS/Fall2021|Fall 2021]]
*[[Applied/ACMS/Spring2021|Spring 2021]]
*[[Applied/ACMS/Fall2020|Fall 2020]]
*[[Applied/ACMS/Spring2020|Spring 2020]]
*[[Applied/ACMS/Fall2019|Fall 2019]]
*[[Applied/ACMS/Spring2019|Spring 2019]]
*[[Applied/ACMS/Fall2018|Fall 2018]]
*[[Applied/ACMS/Spring2018|Spring 2018]]
*[[Applied/ACMS/Fall2017|Fall 2017]]
*[[Applied/ACMS/Fall2017|Fall 2017]]
*[[Applied/ACMS/Spring2017|Spring 2017]]
*[[Applied/ACMS/Spring2017|Spring 2017]]

Latest revision as of 21:41, 22 January 2025


Applied and Computational Mathematics Seminar


Spring 2025

Date Speaker Title Host(s)
Jan 31 Thomas Chandler (UW) TBA
Feb 7 Adrian Fraser (Colorado) Destabilization of transverse waves by periodic shear flows Spagnolie
Feb 14 TBA
Feb 21 TBA
Feb 28 Nick Boffi (CMU) TBA Li
Mar 7 TBA
Mar 14 Yue Lu (Harvard) [Colloquium] TBA Li
Mar 21 Genia Vogman (LLNL) TBA Li
Mar 28 Spring Break
Apr 4 TBA
Apr 11 Pierre Lermusiaux (MIT) TBA Chen
Apr 18 Jack Xin (UC Irvine) [Colloquium] TBA
Apr 25 Bernardo Cockburn (Minnesota) Transforming stabilization into spaces Stechmann, Fabien
May 2 Sylvia Herbert (UCSD) TBA Chen

Abstracts

Adrian Fraser (Colorado)

Title: Destabilization of transverse waves by periodic shear flows

Periodic shear flows have the peculiar property that they are unstable to large-scale, transverse perturbations, and that this instability proceeds via a negative-eddy-viscosity mechanism (Dubrulle & Frisch, 1991). In this talk, I will show an example where this property causes transverse waves to become linearly unstable: a sinusoidal shear flow in the presence of a uniform, streamwise magnetic field in the framework of incompressible MHD. This flow is unstable to a KH-like instability for sufficiently weak magnetic fields, and uniform magnetic fields permit transverse waves known as Alfvén waves. Under the right conditions, these Alfvén waves become unstable, presenting a separate branch of instability that persists for arbitrarily strong magnetic fields which otherwise suppress the KH-like instability. After characterizing these waves with the help of a simple asymptotic expansion, I will show that they drive soliton-like waves in nonlinear simulations. With time permitting, I will discuss other fluid systems where similar dynamics are or may be found, including stratified flows and plasma drift waves.

Bernardo Cockburn (Minnesota)

Title: Transforming stabilization into spaces

In the framework of finite element methods for ordinary differential equations, we consider the continuous Galerkin method (introduced in 72) and the discontinuous Galerkin method (introduced in 73/74). We uncover the fact that both methods discretize the time derivative in exactly the same form, and discuss a few of its consequences. We end by briefly describing our ongoing work on the extension of this result to some Galerkin methods for partial differential equations.

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