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Full-Text Articles in Engineering
Turbulence, Entrainment And Low-Order Description Of A Transitional Variable-Density Jet, Bianca Viggiano, Tamara S. Dib, N. Ali, L. G. Mastin, Raúl Bayoán Cal, S. A. Solovitz
Turbulence, Entrainment And Low-Order Description Of A Transitional Variable-Density Jet, Bianca Viggiano, Tamara S. Dib, N. Ali, L. G. Mastin, Raúl Bayoán Cal, S. A. Solovitz
Mechanical and Materials Engineering Faculty Publications and Presentations
Geophysical flows occur over a large range of scales, with Reynolds numbers and Richardson numbers varying over several orders of magnitude. For this study, jets of different densities were ejected vertically into a large ambient region, considering conditions relevant to some geophysical phenomena. Using particle image velocimetry, the velocity fields were measured for three different gases exhausting into air – specifically helium, air and argon. Measurements focused on both the jet core and the entrained ambient. Experiments considered relatively low Reynolds numbers from approximately 1500 to 10 000 with Richardson numbers near 0.001 in magnitude. These included a variety of …
Conditional Averaging And Classification In The Near Wake Of A Wind Turbine Array Boundary Layer, Sarah E. Smith
Conditional Averaging And Classification In The Near Wake Of A Wind Turbine Array Boundary Layer, Sarah E. Smith
Undergraduate Research & Mentoring Program
Flow perturbation induced by interaction with a turbine rotor produces considerable turbulence which can alter the productivity of subsequent units within a wind farm. Previous methods have characterized near wake vorticity of a single turbine as well as recovery distance for various turbine array configurations. This study aims to build from previous methods of analysis from the perspective of the rotor well within a turbine array and develop a model to examine points of significant imposition in relation to rotational effects. Hot wire anemometry was employed downstream of a turbine located in the middle of the third row in a …
Inverse Structure Functions In The Canonical Wind Turbine Array Boundary Layer, Bianca Viggiano, Moira Gion, Naseem Ali, Murat Tutkun, Raúl Bayoán Cal
Inverse Structure Functions In The Canonical Wind Turbine Array Boundary Layer, Bianca Viggiano, Moira Gion, Naseem Ali, Murat Tutkun, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
Wind tunnel measurements for a 3×3 canonical wind turbine array boundary layer are obtained using hot-wire anemometer velocity signals. Two downstream locations are considered, referring to the near- and far-wake, and 21 vertical points are acquired per profile. Velocity increments and exit distances are used to quantify inverse structure functions at both downstream locations. Inverse structure functions in the near-wake show a similar profile for the main vertical locations, but diverge as the moment is increased. In the far-wake, inverse structure functions converge toward a single function for all vertical location and moments. The scaling exponents for inverse structure functions …
Structure Functions, Scaling Exponents And Intermittency In The Wake Of A Wind Turbine Array, Naseem Ali, Aleksandr Sergeyevich Aseyev, Raúl Bayoán Cal
Structure Functions, Scaling Exponents And Intermittency In The Wake Of A Wind Turbine Array, Naseem Ali, Aleksandr Sergeyevich Aseyev, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
Hot-wire measurements obtained in a 3 × 3 wind turbine array boundary layer are utilized to analyze high order structure functions, intermittency effects as well as the probability density functions of velocity increments at different scales within the energy cascade. The intermittency exponent is found to be greater in the far-wake region in comparison with the near-wake. At hub height, the intermittency exponent is found to be null. Extended self-similarity scaling exponents of the second, fourth, and fifth order structure functions remain relatively constant as a function of height in the far-wake; whereas in the near-wake, these are highly affected …
Design For Fractal Grid Generated Turbulence, Moira Gion
Design For Fractal Grid Generated Turbulence, Moira Gion
Undergraduate Research & Mentoring Program
Fractal geometry can be used to find organization or order in something that appears to be in disorder, or chaos. Turbulence is viewed as one place where fractal geometry can be found in nature. The irregularity in fluid flow is dependent on the initial conditions. In the past, the idea of self-similarity has been used to develop statistical theories of energy cascade in a turbulent flow. Recent studies have done experiments on obstructing flows with fractal objects to observe intermittency, (or self-similarity) within a turbulent flow. Experiments on fractal grid generated turbulence has been performed by other research groups, so …
Anisotropy Of The Reynolds Stress Tensor In The Wakes Of Wind Turbine Arrays In Cartesian Arrangements With Counter-Rotating Rotors, Nicholas Hamilton, Raúl Bayoán Cal
Anisotropy Of The Reynolds Stress Tensor In The Wakes Of Wind Turbine Arrays In Cartesian Arrangements With Counter-Rotating Rotors, Nicholas Hamilton, Raúl Bayoán Cal
Mechanical and Materials Engineering Faculty Publications and Presentations
A 4 × 3 wind turbine array in a Cartesian arrangement was constructed in a wind tunnel setting with four configurations based on the rotational sense of the rotor blades. The fourth row of devices is considered to be in the fully developed turbine canopy for a Cartesian arrangement. Measurements of the flow field were made with stereo particle-image velocimetry immediately upstream and downstream of the selected model turbines. Rotational sense of the turbine blades is evident in the mean spanwise velocity W and the Reynolds shear stress −vw. The flux of kinetic energy is shown to be of greater …