Sökning: "high frequency waves"
Visar resultat 1 - 5 av 184 avhandlingar innehållade orden high frequency waves.
1. Steady waves in local and nonlocal models for water waves
Sammanfattning : We study the steady Euler equations for inviscid, incompressible, and irrotational water waves of constant density. The thesis consists of three papers. The first paper approaches the Euler equations through a famous nonlocal model equation for gravity waves, namely the Whitham equation. LÄS MER
2. Uncertainty quantification for high frequency waves
Sammanfattning : We consider high frequency waves satisfying the scalar wave equationwith highly oscillatory initial data. The speed of propagation of the mediumas well as the phase and amplitude of the initial data is assumed to beuncertain, described by a finite number of independent random variables withknown probability distributions. LÄS MER
3. Uncertainty quantification for high frequency waves
Sammanfattning : We consider high frequency waves satisfying the scalar wave equation with highly oscillatory initial data represented by a short wavelength ε. The speed of propagation of the medium as well as the phase and amplitude of the initial data is assumed to be uncertain, described by a finite number of independent random variables with known probability distributions. LÄS MER
4. Fast Adaptive Numerical Methods for High Frequency Waves and Interface Tracking
Sammanfattning : The main focus of this thesis is on fast numerical methods, where adaptivity is an important mechanism to lowering the methods' complexity. The application of the methods are in the areas of wireless communication, antenna design, radar signature computation, noise prediction, medical ultrasonography, crystal growth, flame propagation, wave propagation, seismology, geometrical optics and image processing. LÄS MER
5. Ultrasonic Arrays for Sensing and Beamforming of Lamb Waves
Sammanfattning : Non-destructive testing (NDT) techniques are critical to ensure integrity and safety of engineered structures. Structural health monitoring (SHM) is considered as the next step in the field enabling continuous monitoring of structures. LÄS MER