The UTRC wind energy conversion system performance analysis for horizontal axis wind turbines (WECSPER)

The theory for the UTRC Energy Conversion System Performance Analysis (WECSPER) for the prediction of horizontal axis wind turbine performance is presented. Major features of the analysis are the ability to: (1) treat the wind turbine blades as lifting lines with a prescribed wake model; (2) solve for the wake-induced inflow and blade circulation using real nonlinear airfoil data; and (3) iterate internally to obtain a compatible wake transport velocity and blade loading solution. This analysis also provides an approximate treatment of wake distortions due to tower shadow or wind shear profiles. Finally, selected results of internal UTRC application of the analysis to existing wind turbines and correlation with limited test data are described

A prescribed wake rotor inflow and flow field prediction analysis, user's manual and technical approach

A user's manual is provided which includes the technical approach for the Prescribed Wake Rotor Inflow and Flow Field Prediction Analysis. The analysis is used to provide the rotor wake induced velocities at the rotor blades for use in blade airloads and response analyses and to provide induced velocities at arbitrary field points such as at a tail surface. This analysis calculates the distribution of rotor wake induced velocities based on a prescribed wake model. Section operating conditions are prescribed from blade motion and controls determined by a separate blade response analysis. The analysis represents each blade by a segmented lifting line, and the rotor wake by discrete segmented trailing vortex filaments. Blade loading and circulation distributions are calculated based on blade element strip theory including the local induced velocity predicted by the numerical integration of the Biot-Savart Law applied to the vortex wake model

Feeding Increasing Levels of Reduced-Oil Distillers Dried Grains with Solubles from Two Ethanol Fermentation Methods Impacts Finishing Pig Growth Performance and Belly Quality

Reduced-oil distillers dried grains with solubles (DDGS) are an affordable source of energy in finishing pig diets, but differences in DDGS fermentation method on finishing pig growth performance and belly quality is relatively unknown. The objectives of this study were: 1) determine the influence of increasing dietary inclusion rate of hot fermentation (HF) and cold fermentation (CF) DDGS on growth performance, carcass characteristics and belly quality, and 2) compare the effect of HF and CF DDGS on finishing pig growth performance, carcass characteristics, and belly quality. Crossbred pigs (n = 200) were used in a randomized complete block design and assigned to one of eight treatments with varying inclusion rates of HF and CF DDGS (0, 20, 40, or 60%) and a diet with 40% inclusion of CF DDGS and withdrawal period. A 5-phase feeding program was utilized with diets formulated to be isocaloric and isolysinic. Pigs were harvested at a commercial abattoir when the average pen weight reached 122.5 kg. Two bellies per pen were collected for analyses. Orthogonal polynomial contrasts were used to determine linear and curvilinear effects. As inclusion rate of CF DDGS increased, overall average daily gain (ADG) and gain to feed ratio (G:F) decreased linearly (P \u3c 0.0001), but HF DDGS did not influence ADG (P \u3e0.24) or G:F (P \u3e0.25). Pigs fed CF DDGS had decreased ADG (P \u3c 0.001) and ADFI (P = 0.03) compared to HF DDGS. As inclusion rate of CF DDGS increased, hot carcass weight decreased linearly (P = 0.02), however, as inclusion rate of HF DDGS increased a quadratic effect was observed (P = 0.04). Carcass yield linearly decreased (P = 0.01) as HF DDGS inclusion increased and tended to decrease linearly (P = 0.08) as CF DDGS inclusion rate increased. Carcass yield was not different between CF and HF DDGS (P = 0.12). As DDGS inclusion rate increased, regardless of fermentation method, belly quality decreased, evidenced by a linear decrease in belly flop scores (P \u3c 0.0001) and percentage of saturated fatty acids (P \u3c .0001). Iodine values (P \u3c 0.0001) and percentage of polyunsaturated fatty acids (P \u3c 0.0001) increased linearly with inclusion rate regardless of fermentation method. Increasing the inclusion rate of HF DDGS did not affect growth performance, but decreased belly quality, however, feeding increasing levels of CF DDGS decreased growth performance and belly quality. Furthermore, pigs fed HF DDGS displayed improved growth performance compared to CF DDGS

Helicopter rotor wake geometry and its influence in forward flight. Volume 2: Wake geometry charts

Isometric and projection view plots, inflow ratio nomographs, undistorted axial displacement nomographs, undistorted longitudinal and lateral coordinates, generalized axial distortion nomographs, blade/vortex passage charts, blade/vortex intersection angle nomographs, and fore and aft wake boundary charts are discussed. Example condition, in flow ratio, undistorted axial location, longitudinal and lateral coordinates, axial coordinates distortions, blade/tip vortex intersections, angle of intersection, and fore and aft wake boundaries are also discussed

Helicopter rotor wake geometry and its influence in forward flight. Volume 1: Generalized wake geometry and wake effect on rotor airloads and performance

An analytic investigation to generalize wake geometry of a helicopter rotor in steady level forward flight and to demonstrate the influence of wake deformation in the prediction of rotor airloads and performance is described. Volume 1 presents a first level generalized wake model based on theoretically predicted tip vortex geometries for a selected representative blade design. The tip vortex distortions are generalized in equation form as displacements from the classical undistorted tip vortex geometry in terms of vortex age, blade azimuth, rotor advance ratio, thrust coefficient, and number of blades. These equations were programmed to provide distorted wake coordinates at very low cost for use in rotor airflow and airloads prediction analyses. The sensitivity of predicted rotor airloads, performance, and blade bending moments to the modeling of the tip vortex distortion are demonstrated for low to moderately high advance ratios for a representative rotor and the H-34 rotor. Comparisons with H-34 rotor test data demonstrate the effects of the classical, predicted distorted, and the newly developed generalized wake models on airloads and blade bending moments. Use of distorted wake models results in the occurrence of numerous blade-vortex interactions on the forward and lateral sides of the rotor disk. The significance of these interactions is related to the number and degree of proximity to the blades of the tip vortices. The correlation obtained with the distorted wake models (generalized and predicted) is encouraging

An unsteady helicopter rotor: Fuselage interaction analysis

A computational method was developed to treat unsteady aerodynamic interactions between a helicopter rotor, wake, and fuselage and between the main and tail rotors. An existing lifting line prescribed wake rotor analysis and a source panel fuselage analysis were coupled and modified to predict unsteady fuselage surface pressures and airloads. A prescribed displacement technique is used to position the rotor wake about the fuselage. Either a rigid blade or an aeroelastic blade analysis may be used to establish rotor operating conditions. Sensitivity studies were performed to determine the influence of the wake fuselage geometry on the computation. Results are presented that describe the induced velocities, pressures, and airloads on the fuselage and on the rotor. The ability to treat arbitrary geometries is demonstrated using a simulated helicopter fuselage. The computational results are compared with fuselage surface pressure measurements at several locations. No experimental data was available to validate the primary product of the analysis: the vibratory airloads on the entire fuselage. A main rotor-tail rotor interaction analysis is also described, along with some hover and forward flight