Conferences, Lectures, & Seminars
Events for March
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Sea Level Rise: How the Oceans Respond to a Warming World
Wed, Mar 04, 2009 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Josh Willis Scientist Jet Propulsion Laboratory Pasadena, CA As the planet heats up, over 80 percent of the excess heat goes toward warming the oceans. In essence, the oceans are the Earth's heat capacitors, absorbing the heat from global warming and setting the time scale for climate change. As they warm, ocean waters expand, causing sea level rise. Rising ocean levels are one of the most serious and visible consequences of global warming. However, projections of future sea level rise remain very crude and have so far underestimated the actual rate of rise. To accurately project sea level rise, it is important to understand its causes. Since 2003, two new global ocean observing systems have begun to address this issue. The Argo array of profiling floats now provides nearly global observations of temperature and salinity in the upper ocean, and the Gravity Recovery and Climate Experiment (GRACE) satellites provide monthly estimates of the ocean's total mass. Using data from these and other instruments, the first attempts to explain the causes of present data sea level rise have been made. Results suggest that although warming and thermal expansion played a large role in sea level rise during the 1990s, the melting of glaciers and ice sheets is accelerating and may have become the dominate source in recent years.
Location: Seaver Science Library, Rm 150
Audiences: Everyone Is Invited
Contact: April Mundy
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Alternative Fuels for Commercial and Military Aviation
Wed, Mar 11, 2009 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Marty Bradley Technical Fellow The Boeing Company Huntington Beach, CA Boeing is working with our military and commercial aviation customers to develop alternative fuels for aviation. In this presentation, Dr. Bradley will discuss a range of alternative fuel options and show why Boeing is concentrating on drop-in replacement fuels for aviation. Synthetic fuels and biofuels will be compared and evaluated for energy efficiency, environmental impact, and sustainability. The suitability of biomass feedstocks will be compared. Dr. Bradley will also discuss recent developments involving progress toward the certification of alternative fuels and recent highly successful commercial and military flight demonstrations.
Location: Seaver Science Library Rm 150
Audiences: Everyone Is Invited
Contact: April Mundy
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The Looming Crisis of Air Traffic Capacity - Can Vortex Dynamics Help
Wed, Mar 25, 2009 @ 03:30 PM - 04:30 PM
Aerospace and Mechanical Engineering
Conferences, Lectures, & Seminars
Fazle HussainDept of Mech Engr, Univ of HoustonCurrently, Moore Distinguished Scholar, CaltechCullen Distinguished ProfessorDirector, Institute of Fluid Dynamics and TurbulenceABSTRACTBy 2025, the air traffic capacity will be tripled, demanding a tripling of runways at major airports of the world. Primarily mandated by aircraft separation for safe flight, this is not only already a challenge during takeoffs and landings, but will become a major problem also during cruise in the crowded skies. Motivated by this scenario, we propose a method of breaking up the trailing vortices and inducing their rapid decay so that separation between aircraft can be significantly reduced, thus minimizing the need for additional runways and flight delays.We study via direct numerical simulation the evolution of a vortex column embedded in fine-scale turbulence. We then explore three potential mechanisms for core perturbation growth:
(a) centrifugal instability due to vortex circulation overshoot, (b) Kelvin wave growth in the core due to resonance with the external turbulence, and (c) transient growth of perturbations in the normal-mode-stable vortex. We
show that transient growth of bending waves can produce orders of magnitude growth in core turbulence and hence possible breakup of trailing vortices and their faster decay - particularly at Reynolds numbers relevant to aircraft trailing vortices.
Location: Seaver Science Library, Rm 150
Audiences: Everyone Is Invited
Contact: April Mundy