Crop residue management received little attention until about 1970. Records of crop residue production are limited, but crop yield databases have been available since 1865. Carbon sequestration and other conservation benefits require a detailed knowledge of crop residue production and management. Our objectives are to: (i) review grain and biomass yield, harvest index (HI), and root C/shoot C r...

The effectiveness of five different turbulence models is assessed for the flow across a row of confined cylinders at a pitch-to-diameter ratio of 1.7 and at Reynolds numbers ranging from 2621 to 55 920. Models examined include the one-equation Spalart-Almaras model; twoequation realizable k «, k v, and shear stress transport models; and a four-equation v2 f model. Quantities compared against pu...

An assessment of unstructured grids for use in Detached-Eddy Simulation (and more generally in Large-Eddy Simulation) of massively separated ows is presented. The role of the grid, its generation and re nement, are considered via calculation of three high-Reynolds number turbulent ows of aerodynamic interest: the massively separated ow over a forebody in cross ow, the ow over a delta wing at 27...

This paper represents the results of an experimental work with measurement of mean velocity along with total pressure contours in 2-D form and validation of the same with numerical results based on the wall y + approach for various turbulent models like, Spalart Alamras, k-ε model, k-ω model and RSM models are used to solve the closure problem. The turbulence models are investigated in the comm...

This paper compares the results of well-known Spalart-Allmares (SA) model and two-fluid for flow around a heated flat plate. These models represent different approaches to problem turbulence. The SA is one-parameter representative RANS models. currently most popular used solve many practical problems. advantage this that its accuracy quite good simple numerical implementation. Therefore, includ...

in this work, harmony search meta-heuristic optimization algorithm has been developed for aerodynamic shape optimization problem for the first time. the aerodynamic shape, which has been investigated, is an airfoil with parces method for its shape parameterization. the problem was minimization of aerodynamic objective function using inverse design method and the objective function has been the ...

A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions throug...

Although several previous studies have reported a potential drag-reducing effect of dimpled surfaces in turbulent boundary layers, there is lack replicability across experiments performed by different research groups. To contribute to the dialogue, we scrutinize one most studied dimple geometries literature, which has diameter 20 mm and depth 0.5 mm. There no general consensus literature on dra...

The need to reduce soil erosion, maximize soil water conservation, and optimize grain production in dryland cropping systems in the Central Great Plains has culminated in development of nontilled fallow systems. These systems have greatly reduced the degree of soil disturbance, and the amount and degree of residue incorporation. The objectives of this study were to evaluate the influence of soi...