Acoustic tracking of ship wakes

Önür, Çağla
Theories about ship wake structure, bubble dynamics, acoustic propagation through bubble clouds, backscattering and target strength of bubble clouds have been investigated and related Matlab simulations have been carried on. Research has been carried on algorithms for ship wake acoustic detection and tracking. Particle filter method has been simulated with Matlab for target tracking using wake echo measurements. Simulation results are promising.


Computational fluid dynamics simulations of ship airwake with a hovering helicopter rotor
Orbay, Ezgi; Uzol, Oğuz; Sezer Uzol, Nilay; Department of Aerospace Engineering (2016)
In this thesis, Computational Fluid Dynamic simulations of ship airwake for a simple ship geometry are performed for the horizontal and inclined deck configurations and also with and without the helicopter rotor over the deck. An actuator disk model is used for the CFD simulations of a rotor model hovering over the flight deck. All of the computations are performed by using a commercial finite volume CFD flow solver. The unstructured tetrahedral grids are generated in the computational domain including ship...
Elliptical Pin Fins as an Alternative to Circular Pin Fins for Gas Turbine Blade Cooling Applications Part 2 Wake Flow Field Measurements and Visualization Using Particle Image Velocimetry
Uzol, Oğuz (null; 2001-06-07)
Extensive wake flow field measurements and visualizations are conducted using particle image velocimetry (PIV) inside the wakes of the elliptical and circular pin fin arrays in order to better understand the flow physics and the loss mechanisms of these devices. The true-mean velocity field inside the wake two diameters downstream of the pin fin arrays is obtained by collecting and ensemble averaging a large number of PIV samples in the midplane of the test section. Additional experiments are also conducted...
Experimental Investigation of the Effects of Winglets on the Tip Vortex Behavior of a Model Horizontal Axis Wind Turbine Using Particle Image Velocimetry
Ostovan, Yasar; Akpolat, M. Tugrul; Uzol, Oğuz (2019-02-01)
This study presents an experimental investigation on the effects of winglets on the near wake flow around the tip region and on the tip vortex characteristics downstream of a 0.94 m diameter three-bladed horizontal axis wind turbine (HAWT) rotor. Phase-locked 2D particle image velocimetry (PIV) measurements are performed with and without winglets covering 120 deg of azimuthal progression of the rotor. The impact of using winglets on the flow field near the wake boundary as well as on the tip vortex characte...
Improving flow structure and natural convection within fin spacings of plate fin heat sinks
Özet, Mehmet Erdem; Tarı, İlker; Department of Mechanical Engineering (2015)
The main objectives of this thesis are to numerically investigate the previously observed recirculation zones and longitudinal vortices that occur in low fin height plate finned horizontal heat sinks and to improve the flow structures and heat transfer in these zones using various approaches with the help of simulations performed using commercially available CFD software. The approaches used for improvements are replacing the outer most fins with higher ones, introducing gaps on the length of the fins in va...
Stability of gold clusters: molecular-dynamics simulations
Erkoç, Şakir (2000-09-01)
Structural stability and energetics of gold clusters, Au, (n = 3-555), have been investigated by molecular-dynamics simulations. An empirical model potential energy function has been used in the simulations. Stable structures of the microclusters for n = 3-13 have been determined by molecular-dynamics simulation. It has been found that gold microclusters prefer to form three-dimensional compact structures. Molecular-dynamics simulations have also been performed for spherical gold clusters generated from FCC...
Citation Formats
Ç. Önür, “Acoustic tracking of ship wakes,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.