scholarly journals Spontaneous Raman Scattering Temperature Measurements and Large Eddy Simulations of Vibrational Non-equilibrium in High-Speed Jet Flames

2016 ◽  
Author(s):  
Heath H. Reising ◽  
Timothy W. Haller ◽  
Noel T. Clemens ◽  
Philip L. Varghese ◽  
Romain Fiévet ◽  
...  
Keyword(s):  
Raman Scattering ◽  
High Speed ◽  
Large Eddy Simulations ◽  
Temperature Measurements ◽  
Jet Flames ◽  
Spontaneous Raman Scattering ◽  
Large Eddy ◽  
Non Equilibrium

Generalized lapse rate formulas for use in entraining CAPE calculations

2021 ◽  
Author(s):  
John M. Peters ◽  
Jake P. Mulholland ◽  
Daniel R. Chavas
Keyword(s):  
Large Eddy Simulations ◽  
Mixed Phase ◽  
Lapse Rate ◽  
Temperature Lapse Rate ◽  
Large Eddy ◽  
Energy Sink ◽  
Entropy Conservation ◽  
Hydrostatic Balance ◽  
New Formula ◽  
Non Equilibrium

AbstractCommon assumptions in temperature lapse rate formulas for lifted air parcels include neglecting mixing, hydrostatic balance, the removal of all condensate once it forms (pseudoadiabatic), and/or the retention of all condensate within the parcel (adiabatic). These formulas are commonly derived from the conservation of entropy, which leads to errors when non-equilibrium mixed-phase condensate is present. To evaluate these assumptions, a new general lapse rate formula is derived from an expression for energy conservation, rather than entropy conservation. This new formula incorporates mixing of the parcel with its surroundings, relaxes the hydrostatic assumption, allows for non-equilibrium mixed-phase condensate, and can be formulated for pseudoadiabatic or adiabatic ascent. The new formula is shown to exactly conserve entropy for reversible ascent. Predictions by the new formula are compared to that of older and less general formulas. The errors in previous formulas arise from the assumption of hydrostatic balance, which results in considerable warm biases due to the neglect of the energy sink from buoyancy. Predictions of ascent with entrainment using the new formula are then compared to parcel properties along trajectories in large eddy simulations. Simulated parcel properties are better predicted by the formula using a diluted analogy to adiabatic ascent, wherein condensate is diluted at the same rate as other parcel properties, than by the diluted analogy to pseudoadiabatic ascent, wherein all condensate is removed. These results suggest that CAPE should be computed with adiabatic, rather than pseudoadiabatic, parcel ascent.

Large-Eddy Simulations and Measurements of a Small-Scale High-Speed Coflowing Jet

AIAA Journal ◽  
2010 ◽  
Vol 48 (5) ◽  
pp. 963-974 ◽  
Author(s):  
Simon Eastwood ◽  
Paul Tucker ◽  
Hao Xia ◽  
Paul Dunkley ◽  
Peter Carpenter
Keyword(s):  
High Speed ◽  
Large Eddy Simulations ◽  
Small Scale ◽  
Large Eddy
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