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 13 of 13 for “"Serration"”.
-
Comparative Analysis of Serrated Trailing Edge Designs on Idealized Aircraft Engine Fan Blades for Noise Reduction
… serrated blade sets consisted of two different serration sizes (1.27 cm and 2.54 cm) and for each different serration size a second set of blades with added trailing edge camber. The cascade row consisted of 8 GE-Rotor-B blades and 7-passages with adjustable tip gap settings. It had an inlet …
-
Boundary Layer Separation Control on a Salient Back-facing Ramp
… the feasibility and the performance of the serration flow control devices on a salient edge where the laminar boundary layer separation is two-dimensional. Three geometries of serrations: a sharp delta, a double delta and a divergent delta are examined on 15° and 30° deflected, …
-
An embedded IoT antenna for smart pavement monitoring system
… antennas used in road pavement, a ground plane serration technique has been studied and applied to the proposed antenna to improve its performance. Simulation and measurement results show that with serrations on the ground plane, the proposed antenna is able provide broadside gain of 3.4 dB …
-
Mathematical modelling of noise generation in turbofan aeroengines using Green’s functions
… that, depending on the parameters, introducing a serration on the leading edge of the aerofoil can reduce the noise significantly. We build an analytical model to investigate the effect of the serrated edge, which again involves solving a differential equation by using a Green’s function. It also …
-
Aeroacoustic transfer of leading edge serrations from single aerofoils to low-pressure fan applications
Leading edge serrations are well-known for their aeroacoustic potential in reducing aerofoil-turbulence interaction noise and are also associated with certain aerodynamic advantages. To prepare leading edge serrations for industrial application, two obstacles remain to be addressed. First is a …
-
Understanding the Impact of a Serrated Trailing Edge on the Unsteady Hydrodynamic Field
… have shown that a trailing edge with sawtooth serrations can reduce trailing edge noise compared to a straight trailing edge, but the mechanism by which sawtooth serrations reduce noise is not fully understood. Previous theoretical models have assumed that the turbulence field convecting past a …
-
Analysis and design of planar slot antennas for RFID applications using characteristic mode theory
… In addition, edge treatment in the form of serrations can be used to improve the bandwidth and radiation properties of thin planar antennas. Although serrations offer a simple technique to improve radiation characteristics of a microstrip antenna, there are no design guidelines or analytical …
-
An experimental investigation of the behavior of Nitinol
… as the R-phase and stress induced martensite serration are investigated. A one-dimensional constitutive model is presented that quantitatively predicts stress-strain and shape memory effect behavior and was developed with the intention of being an engineering design tool for SMA force …
-
Modifications of Coherent Structures in Fan Blade Wakes for Broadband Noise Reduction
… trailing edge blades (with two different serration sizes and with two trailing edge cambers) and three sets of blades with trailing edge blowing (a simple rectangular slot, rectangular slot with Kuethe-vane vortex generators, and rectangular slot with serrated lips) were tested. The …
-
Mechanical property of body-thoroughly enhanced austenitic stainless steel and high-Mn steel by industry-applicable 3-axis stress-released impact
… atom pair at different stages of an individual serration, we prove that the PLC effect is not caused by the direct interaction between the dislocations and the C atoms, as the previous models proposed. Instead, it is caused by two separate processes involving the returning of the C atoms from …
-
Bio-Inspired Axial Fan Design, 3D Printing Fabrication and Characterization for Noise and Flow Performance Optimization
… mechanisms of owls, bio-inspired trailing-edge serrations are then investigated as a passive control strategy for noise reduction in airfoil-based configurations relevant to axial fans. A hybrid numerical–experimental methodology, based on Large Eddy Simulations (LES) of the incompressible …
-
A multiscale study on the origins of the Portevin-Le Chatelier effect in polycrystalline nickel-based superalloys
… A characterisation of the macroscopic serration and strain localisation characteristics is first presented, through optical Digital Image Correlation (DIC). From this, load drops are unambiguously associated with the presence of bursts of localised strain within so-called Lüders bands. …
-
Elevated temperature mechanical properties of line pipe steels
… nucleation was associated with relatively high serration frequencies and was typically observed at relatively high temperatures within the DSA regime. The critical strain required for serrated flow was greatest at the upper and lower boundaries for serrated flow. Negative strain rate …