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Full-Text Articles in Engineering
Uncertainty Propagation And Robust Design In Cfd Using Sensitivity Derivatives, Michele M. Putko
Uncertainty Propagation And Robust Design In Cfd Using Sensitivity Derivatives, Michele M. Putko
Mechanical & Aerospace Engineering Theses & Dissertations
This study investigates and demonstrates a methodology for uncertainty propagation and robust design in Computational Fluid Dynamics (CFD). Efficient calculation of both first- and second-order sensitivity derivatives is requisite in the proposed methodology. In this study, first- and second-order sensitivity derivatives of code output with respect to code input are obtained through an efficient incremental iterative approach.
An approximate statistical moment method for uncertainty propagation is first demonstrated on a quasi one-dimensional (1-D) Euler CFD code. This method is then extended to a two-dimensional (2-D) subsonic inviscid model airfoil problem. In each application, given statistically independent, random, normally distributed input …
Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue
Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue
Mechanical & Aerospace Engineering Theses & Dissertations
Naturally nanofluidics has applications demanding the samples to be handled in exceedingly small quantities due to the small size of the fluidic channels in nanofluidic devices, such as characterization of single biomolecules. Fluids confined in channels of nanometer characteristic dimensions exhibit physical behaviors not observed in large conduits. Charge properties of the nanochannel wall in contact with an aqueous solution play essential roles in the involved electrokinetic transport phenomena occurring in nanofluidic devices. In addition to tuning the charge properties of the nanofluidic channel wall by adjusting the solution properties such as pH and background salt concentration, field effect transistor …
Analysis Of Human Thermal Comfort Using A Coupled Model For Predicting Human Body-Environment Heat And Mass Exchange, Ahmed M. Al-Mogbel
Analysis Of Human Thermal Comfort Using A Coupled Model For Predicting Human Body-Environment Heat And Mass Exchange, Ahmed M. Al-Mogbel
Mechanical & Aerospace Engineering Theses & Dissertations
Recent advances in computational fluid dynamics (CFD) make it possible to accurately predict many features of airflow within ventilated spaces. The present study investigates thermal comfort aspects of an occupant in a conditioned space, using a CFD code.
The heat and mass transfer between the human body and the surrounding environment is analyzed by a coupled model that accounts for dispersal of metabolically generated heat in the body to the surroundings by the combined mechanisms of radiation, convection, respiration and evaporation. A two-node model in which two coupled non-linear algebraic equations govern the skin temperature and the body core temperature …
Computation Of Shock Induced Noise In Imperfectly Expanded Supersonic Jets, Bulent Imamoglu
Computation Of Shock Induced Noise In Imperfectly Expanded Supersonic Jets, Bulent Imamoglu
Mechanical & Aerospace Engineering Theses & Dissertations
Screech noise exists only in imperfectly expanded jets. The exit pressure of imperfectly expanded jets does not match ambient pressure, so expansion or compression waves appear out of the nozzle and generate shock cell patterns. Screech is generated by the interaction of shock cells and instability waves. Many experiments and computations have been done to model screech noise, but it is not yet a very well known subject.
A numerical study is performed to understand screech generation mechanisms and to compare with latest experiments. A supersonic underexpanded jet of 25.4 mm diameter is modeled for cases of Mach numbers of …