Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 10 of 10 for “"spectral proper orthogonal decomposition"”.
-
Model order reduction in the frequency domain via spectral proper orthogonal decomposition
… systems. Specifically, we emphasize the usage of spectral proper orthogonal decomposition (SPOD), recently revived by Towne et. al. (2018), which results in sets of orthogonal modes, each oscillating at a single frequency, that are said to optimally represent coherent-structures evolving in space …
-
Contributions to the Understanding of Ship Airwakes Using Advanced Flow Diagnostic Techniques
… behind the funnel and above the flight deck. Proper Orthogonal Decomposition and Spectral Proper-Orthogonal Decomposition was used to extract the dominant energy modes from the TR-PIV measurements to better quantify the complex unsteady flow structures exhibited in the airwake. The application …
-
Aerodynamic Interactions in Vortex Tube Separator Arrays
… contains only low levels of anisotropy. Spectral proper orthogonal decomposition is conducted on the array flow; it reveals the existence of low-frequency harmonic behavior composed of back-and-forth pumping motions downstream of the central VTS. Additionally, a unique precession motion …
-
Simulation of Flow in a Solid Fuel Ramjet Cavity
… implemented and investigated in twodimensions. Spectral Proper Orthogonal Decomposition is used to analyze CFD results to determine acoustic modes in the ramjet. Peak acoustic frequencies are compared between between numerical and experimental results. Comparisons are made between simulations …
-
Aeroacoustics Applications to Jets and Rotors
… frequency modes of coherent structures. Through Spectral Proper Orthogonal Decomposition (SPOD), the study identifies the impact of actuation on the energy distribution across the frequency spectrum. Results demonstrate a measurable reduction in Overall Sound Pressure Level (OASPL), particularly …
-
The Effect of Thermal Non-Uniformity on Coherent Structures in Supersonic Free Jets
… to the thermally uniform case. The method of spectral proper orthogonal decomposition (SPOD) was used to reveal the large-scale, coherent noise producing mechanisms. SPOD results indicate that the thermally non-uniform case showed a decrease in turbulent kinetic energy compared to the uniform …
-
An experimental investigation of transverse jets in supersonic crossflow
… argon cases due to these moving shocks. Power Spectral Density (PSD) of schlieren image pixel light intensity shows that the peak frequency of vortex shedding is inversely proportional to the momentum flux ratio J and this may be due to the level of compressibility. At the same J, the peak …
-
Prediction & Active Control of Multi-Rotor Noise
… are performed. Near field flow and acoustic properties were resolved using Hybrid LES-Unsteady RANS approach. Far-field sound predictions were performed using Ffowcs-Williams-Hawkings formulation. The two-propeller results in hovering are compared with that of the single propeller. This …
-
Propeller Noise Prediction of an Urban Air Mobility Vehicle in Urban Environment
… Theoretical analysis and SPOD-based flow decomposition confirm that the proposed convective-spacing model accurately captures the spacing between dominant pressure-fluctuation structures near the propeller tip. This validates the physical basis for end-cap spacing and demonstrates that …
-
The Effects of Porous Inert Media in a Self-Excited Thermoacoustic Instability: A Study of Heat Release and Reduced Order Modelling
… The velocity results were decomposed using a spectral proper orthogonal decomposition (SPOD) method. The energy breakdown showed how PIM reduced and distributed the energy in the flow structures, creating a more stable flow field. Heat release results with velocity information demonstrated the …