Sökning: "resolvent"

Visar resultat 1 - 5 av 15 avhandlingar innehållade ordet resolvent.

1. 1. Modelling and control of turbulent and transitional flows

   Författare :Pierluigi Morra; Dan S. Henningson; Ardeshir Hanifi; André V. G. Cavalieri; Shervin Bagheri; Aimee S. Morgans; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reduced order modeling; flow control; resolvent analysis; transi- tional boundary layer; turbulent boundary layer; drag reduction; high-fidelity wall-turbulence modelling; modellreduktion; strömningskontroll; resolvent analys; laminär- turbulent omslag; turbulent gränsskikt; motståndsminskning; väggturbulens modellering; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : The dynamics of fluid motion can accurately be described by the Navier– Stokes equations. Manipulating these equations to reduce their complexity but preserving their main characteristics has always been a key research activity in the field of fluid mechanics. LÄS MER

3. 2. Stability of plane Couette flow and pipe Poiseuille flow

   Författare :Per-Olov Åsén; Gunilla Kreiss; Jonathan Goodman; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hydrodynamic stability; plane Couette flow; pipe Poiseuille flow; direct numerical simulations; resolvent; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : This thesis concerns the stability of plane Couette flow and pipe Poiseuille flow in three space dimensions. The mathematical model for both flows is the incompressible Navier--Stokes equations. Both analytical and numerical techniques are used. We present new results for the resolvent corresponding to both flows. LÄS MER

4. 3. Some Resolvent Estimates in Harmonic Analysis

   Författare :Anders Dahlner; Matematik (naturvetenskapliga fakulteten); []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; field theory; Number Theory; algebra; algebraic geometry; Talteori; group theory; Tauberian theorem. Quantitative inversion. Cesaro operator. Bishops property beta.; algebraisk geometri; fältteori; gruppteori;

   Sammanfattning : This thesis contains three papers about three different estimates of resolvents in harmonic analysis. These papers are: Paper 1. ``A Wiener tauberian theorem for weighted convolution algebras of zonal functions on the automorphism group of the unit disc'' Paper 2. ``Uniform spectral radius and compact Gelfand transform'' Paper 3. LÄS MER

5. 4. Theoretical quantum optics with giant atoms

   Författare :Ariadna Soro Álvarez; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; continuous waveguides; master equation; artificial atoms; structured waveguides; Quantum optics; waveguide quantum electrodynamics; resolvent formalism; SLH formalism; giant atoms; open quantum systems;

   Sammanfattning : Giant atoms have emerged as new paradigm in quantum optics during the last decade. These are quantum emitters that couple to light—or other bosonic fields—at multiple discrete points, which can be spaced wavelengths apart. LÄS MER

7. 5. Non-selfadjoint operator functions

   Författare :Axel Torshage; Christian Engström; Marco Marletta; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Non-linear spectral problem; numerical range; pseudospectrum; resolvent estimate; equivalence after extension; block operator matrices; operator functions; operator pencil; spectral divisor; joint numerical range; Mathematics; matematik;

   Sammanfattning : Spectral properties of linear operators and operator functions can be used to analyze models in nature. When dispersion and damping are taken into account, the dependence of the spectral parameter is in general non-linear and the operators are not selfadjoint. LÄS MER