LES of Contrails With Ice Habit Treatment Using the Fickian-Distribution Model

2014 ◽  
Author(s):  
Aniket R. Inamdar ◽  
Sanjiva K. Lele ◽  
Mark Z. Jacobson
Keyword(s):  
Crystal Growth ◽  
Large Eddy Simulation ◽  
Laboratory Data ◽  
Distribution Model ◽  
Ice Crystal ◽  
Ambient Temperatures ◽  
Eddy Simulation ◽  
Large Eddy ◽  
In Situ Observations

This study uses a Fickian-Distribution parameterization [Chen & Lamb, 1994] to model the effects of ice habits on contrail formation within a large eddy simulation (LES). Box model cases were first performed at various ambient temperatures and relative humidities over ice (RHi) and results compared with available laboratory data of ice crystal growth and habit distribution [Bailey & Hallett, 2004]. The model was then used in a full 3-D LES of contrails and results were compared with in-situ observations [Febvre et. al., 2009]. Comparisons are also made with results from simulations that used a probabilistic ice habit model [Inamdar et. al., 2013].

scholarly journals Large-eddy simulation of the ice shelf-ocean boundary layer and heterogeneous refreezing rate by sub-ice shelf plume

2020 ◽  
Author(s):  
Ji Sung Na ◽  
Taekyun Kim ◽  
Emilia Kyung Jin ◽  
Seung-Tae Yoon ◽  
Won Sang Lee ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Outer Region ◽  
Ice Shelf ◽  
Salinity Field ◽  
Eddy Simulation ◽  
Large Eddy ◽  
In Situ Observations ◽  
Ocean Boundary

Abstract. The role of the refreezing effect in the ice shelf–ocean boundary layer (IOBL) flow with a super-cooled, plume beneath the ice shelf is investigated using the large-eddy simulation. To reveal the detailed physical processes and characteristics of the IOBL flow, a model domain is initialized and forced by in situ observations and a comparison is made between two simulations, one with the refreezing effect and one without. The simulated velocity, potential temperature, and salinity field are validated with in situ observations performed in Terra Nova Bay in the western Ross Sea in 2016/2017, confirming that the vertical structures in the simulation results agree well with observations. In particular, it is evident that, when the refreezing effect is considered, the IOBL flow can be more realistically resolved, especially upward advection from the sub-ice shelf plume and the ice front eddy. Beneath the ice shelf, two district regions (the inner and outer regions) are identified based on flow characteristics and the refreezing pattern. In the inner region, stratification and stable conditions are observed with negative momentum flux and low refreezing rates. Meanwhile, in the outer region, high shear impact and unstable conditions with a heat flux of −9 to −52 W m−2 are observed, demonstrating the high refreezing rate and the entrainment of super-cooled water from the sub-ice shelf plume. A total of 94 % of the refreezing events occur in the outer region, with a maximum refreezing rate of 1.86 m yr−1 at the ice front.

scholarly journals Effects of ambient methanol on pollutants formation in dual-fuel spray combustion at varying ambient temperatures: A large-eddy simulation

2020 ◽  
Vol 279 ◽  
pp. 115774 ◽  
Author(s):  
Shijie Xu ◽  
Shenghui Zhong ◽  
Kar Mun Pang ◽  
Senbin Yu ◽  
Mehdi Jangi ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Fuel Spray ◽  
Spray Combustion ◽  
Dual Fuel ◽  
Ambient Temperatures ◽  
Eddy Simulation ◽  
Large Eddy

Large eddy simulation modelling of combustion for propulsion applications

2009 ◽  
Vol 367 (1899) ◽  
pp. 2957-2969 ◽  
Author(s):  
C. Fureby
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Internal Combustion Engines ◽  
Laboratory Data ◽  
Predictive Modelling ◽  
Simulation Modelling ◽  
Eddy Simulation ◽  
Scramjet Combustor ◽  
Large Eddy

Predictive modelling of turbulent combustion is important for the development of air-breathing engines, internal combustion engines, furnaces and for power generation. Significant advances in modelling non-reactive turbulent flows are now possible with the development of large eddy simulation (LES), in which the large energetic scales of the flow are resolved on the grid while modelling the effects of the small scales. Here, we discuss the use of combustion LES in predictive modelling of propulsion applications such as gas turbine, ramjet and scramjet engines. The LES models used are described in some detail and are validated against laboratory data—of which results from two cases are presented. These validated LES models are then applied to an annular multi-burner gas turbine combustor and a simplified scramjet combustor, for which some additional experimental data are available. For these cases, good agreement with the available reference data is obtained, and the LES predictions are used to elucidate the flow physics in such devices to further enhance our knowledge of these propulsion systems. Particular attention is focused on the influence of the combustion chemistry, turbulence–chemistry interaction, self-ignition, flame holding burner-to-burner interactions and combustion oscillations.

scholarly journals Large-eddy simulation of dual-fuel spray ignition at different ambient temperatures

2020 ◽  
Vol 215 ◽  
pp. 51-65 ◽  
Author(s):  
Bulut Tekgül ◽  
Heikki Kahila ◽  
Ossi Kaario ◽  
Ville Vuorinen
Keyword(s):  
Large Eddy Simulation ◽  
Fuel Spray ◽  
Dual Fuel ◽  
Ambient Temperatures ◽  
Eddy Simulation ◽  
Large Eddy
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