A small flag attached to the surface of an airfoil near leading-edge exhibits self-excited oscillations when is set at a post-stall angle attack. The limit cycle between and freestream produce vortices periodically, resulting in remarkable increase maximum lift coefficient stall angle. There are strong similarities this passive flow control method, which relies on fluid-structure interactions, ...

Department of Aeronautical and Astronautical Engineering, University of Illinois at Urbana-Champaign, 306 Talbot Laboratory, 104 S. Wright Street Urbana. IL 61801-2935 The effects of rime ice on horizontal axis wind turbine performance were estimated. For typzcal supercooled fog conditions found in cold northern regions, four rime ice accretwns on the 5809 wmd turbine airfoil were predicted usi...

Observations are presented of several novel phenomena involved in the dynamics of a pendant drop of viscoelastic micellar fluid falling through air. Generally, when a drop falls a filament forms connecting it to the orifice; the filament eventually breaks due to an instability. The filament dynamics and instabilities reported here are very different from the standard Newtonian and non-Newtonian...

Axial flow compressors are subjected to demands for ever-increasing levels of pressure ratio at a compression efficiency that augments the overall cycle efficiency. However, unstable flow may develop in the compressor, which can lead to a stall or surge and subsequently to gas turbine failure resulting in significant downtime and cost to repair. To protect against these potential aerodynamic in...

An examination of fertility trends in countries with multiple DHS surveys found that in the 1990s fertility stalled in mid-transition in seven countries: Bangladesh, Colombia, Dominican Republic, Ghana, Kenya, Peru, and Turkey. In each of these countries fertility was high (>6 births per woman) in the 1950s and then declined to fewer than 5 births per woman in the early or mid-1990s, before sta...

Studies show that agricultural and animal feeding operations (AFOs) contribute a considerable amount of ammonia (NH3) to the atmosphere. Agricultural NH3 emissions are recognized as an important air quality issue. Biological decomposition of manure from dairy operations results in emissions of NH3 and other gases. There is a need to determine NH3 emission factors (EFs) to compile annual NH3 inv...

An examination of fertility trends in countries with multiple DHS surveys found that in the 1990s fertility stalled in midtransition in seven countries: Bangladesh, Colombia, Dominican Republic, Ghana, Kenya, Peru, and Turkey. In each of these countries fertility was high (more than six births per woman) in the 1950s and declined to fewer than five births per woman in the early or mid-1990s, be...

BACKGROUND Prophylactic measures are key components of dairy herd mastitis control programs, but some are only relevant in specific housing systems. To assess the association between management practices and mastitis incidence, data collected in 2011 by a survey among 979 randomly selected Swiss dairy farms, and information from the regular test day recordings from 680 of these farms was analyz...