Turbulent flow field predictions in sharply curved turn-around ducts

Two-dimensional turbulent flow of incompressible Newtonian fluids in sharply curved 180 deg turn around ducts is studied. Results of an approximate numerical flow field analysis utilizing an orthogonal, body-fitted, curvilinear coordinate system are compared to results based on a traditional cylindrical reference frame. Qualitative induction of general streamfield characteristics as well as quantitative benchmarks for the planning of future experimentation are provided. In addition, preliminary results of an augmented kappa - epsilon turbulence model analysis, which explicitly accounts for the effects of streamline curvature and pressure strain in internal turbulent flows, are presented. Specific model difficulties are discussed and comparisons with standard kappa - epsilon model predictions are included

Sharply curved turn around duct flow predictions using spectral partitioning of the turbulent kinetic energy and a pressure modified wall law

Computational predictions of turbulent flow in sharply curved 180 degree turn around ducts are presented. The CNS2D computer code is used to solve the equations of motion for two-dimensional incompressible flows transformed to a nonorthogonal body-fitted coordinate system. This procedure incorporates the pressure velocity correction algorithm SIMPLE-C to iteratively solve a discretized form of the transformed equations. A multiple scale turbulence model based on simplified spectral partitioning is employed to obtain closure. Flow field predictions utilizing the multiple scale model are compared to features predicted by the traditional single scale k-epsilon model. Tuning parameter sensitivities of the multiple scale model applied to turn around duct flows are also determined. In addition, a wall function approach based on a wall law suitable for incompressible turbulent boundary layers under strong adverse pressure gradients is tested. Turn around duct flow characteristics utilizing this modified wall law are presented and compared to results based on a standard wall treatment

Iterative procedures for space shuttle main engine performance models

Performance models of the Space Shuttle Main Engine (SSME) contain iterative strategies for determining approximate solutions to nonlinear equations reflecting fundamental mass, energy, and pressure balances within engine flow systems. Both univariate and multivariate Newton-Raphson algorithms are employed in the current version of the engine Test Information Program (TIP). Computational efficiency and reliability of these procedures is examined. A modified trust region form of the multivariate Newton-Raphson method is implemented and shown to be superior for off nominal engine performance predictions. A heuristic form of Broyden's Rank One method is also tested and favorable results based on this algorithm are presented

Validation of the space shuttle main engine steady state performance model

The primary objective was to present methods for validating predictions of Rocketdyne's most current version of the Space Shuttle Main Engine (SSME) Power Balance Model (PBM) with respect to physical relations governing flow systems. This required the development and implementation of postprocessors to check results of PBM computations for satisfaction of conservation relations. A cursory uncertainty analysis of PBM predictions with respect to mass and energy balances was performed. In addition, an effort to identify the empirical relations and physical assumptions within PBM which impact the ability of the model to attain rigorous balance was begun

Cholesterol and Malondialdehyde Contents of Broiler-Chicken Meat Supplemented with Indigofera Zolingeriana Top Leaf Meal

This research aimed to increase functional value of broiler-chicken meat containing high antioxidant and low cholesterol through substitution of soybean meal (SBM) with Indigofera zollingeriana top leaf meal (ILM). The experiment used 160 day old broiler chicken (Cobb strain). The experimental chicken were provided dietary treatments when they were 15-days old (initial body weight of 460.5±1.56 g/bird) and terminated on day 35. A completely randomized design (CRD) with four treatments and four replications and ten birds in each replication was used in this experiment. Dietary treatments were: R1= diet containing 20% soybean meal (SBM) without I. zollingeriana top leaf meal (ILM); R2= diet containing 16% SBM and 5.9% ILM; R3= diet containing 12% SBM and 11.8% ILM; R4= diet containing 8% SBM and 17.74% ILM. Variables measured were performances (feed consumption, body weight gain, and feed conversion) and the quality of broiler meat (cholesterol, fat content, and malondialdehyde [MDA] concentration). The results showed that supplementation of 17.74% ILM (R4) as the substitution of 60% soybean meal protein produced the same performances of broilers as those of control diet (R1). Supplementation of 11.8% ILM as the substitution of 40% soybean meal protein (R3) decreased meat cholesterol by 34.70%, meat fat content by 52.93%, and MDA concentration by 62.52%. The conclusion of this study was that supplementation of 17.74% ILM produced the same performances as that of control diet, increased antioxidant content of the meat, indicated by a lower MDA concentration, and decreased cholesterol, as well as fat content of broiler-chicken meat

Dynamic hysteresis in Finemet thin films

We performed a series of dynamic hysteresis measurements on three series of Finemet films with composition Fe$_{73.5}$Cu$_1$Nb$_3$Si$_13.5$B$_9$, using both the longitudinal magneto-optical Kerr effect (MOKE) and the inductive fluxometric method. The MOKE dynamic hysteresis loops show a more marked variability with the frequency than the inductive ones, while both measurements show a similar dependence on the square root of frequency. We analyze these results in the frame of a simple domain wall depinning model, which accounts for the general behavior of the data.Comment: 3 pages, 3 figure

Fungsi dan Kategori Frasa Preposisional pada Kalimat Sederhana dalam Novel Brandsetters Karya Natasha Alessandra (suatu Analisis Sintaksis)

This research is entitled “Function and Category of Prepositional Phrase in the Simple Sentence in the Brandsetters Novel by Natasha Alessandra” is a syntactic analysis which describes the functions and categories of the prepositional phrase in the simple sentence. This research is an attempt to identify, classify, and analyze the prepositional phrase in the simple sentence found in the novel in terms of functions and categories. This is a descriptive study that used the concept of Aarts and Aarts (1982). The results of this research show that prepositional function in a sentence can be divided into, function as a subject, as a subject attribute, as an object attribute, as a predicator complement, and as an adverbial. In the simple sentence structure, the functions found externally are subject, predicate, and adverbial. Internally, the functions found are predicator and complement which realized by subject attribute, object attribute, and predicator complement. The categories found in the simple sentence are noun phrase, verb phrase, adjective phrase, adverbial phrase, and prepositional phrase. Internally, only the structures of the prepositional phrase which is analyzed. The internal structure of prepositional phrase found are prepositional which realized by category preposition, and prepositional complement which realized by category noun phrase, noun, or pronoun

Pemanfaatan Biochar Asal Cangkang Kelapa Sawit Untuk Meningkatkan Serapan Hara Dan Sekuestrasi Karbon Pada Media Tanah Lithic Hapludults Di Pembibitan Kelapa Sawit

. The potential of biochar derived from oil palm kernel shell to be used as a soil amendment seems promising for sustaining oil palm plantation in marginal land. This study was conducted to investigate the effects of three biochar dosages (50; 100; and 150 gram) in combination with 75% NPK-Mg dosages per seedling on the growth of oil palm seedling, nutrient uptake and carbon sequestration in the nursery stage. A field experiment was conducted at PT Astra Agro Lestari Tbk, Central Kalimantan in March 2015- April 2016. Experiment was arranged in a completely randomized block design (CRBD) with five treatments and twenty replications i.e: (i) 100% standard dosage NPK-Mg per seed (control); (ii) 75% standard dosage NPK-Mg per seed; (iii) 75% standard dosage NPK-Mg + 50 g biochar per seed; (iv) 75% standard dosage NPK-Mg + 100 g biochar per seed; and (v) 75% standard dosage NPK-Mg + 150 g biochar per seed. The best vegetative growth performance of oil palm seedlings in Lithic Hapludults soil was shown by the application of 75% standard dosage of NPK-Mg fertilizers in combination with 150 gram biochar per seed. This treatment increased height (33.9%); leaf number (36.2%); stem diameter (28.9%); length and width of the leaf (22.6 and 33.3%), dry weight of oil palm seedlings, especially roots (65.2%), CEC (17.2%), and organic C (26.9%). This treatment also showed the highest absorption of N in leaves of oil palm seedlings, but no differences were observed for P and K uptakes compared to the treatment of 100% dosage of NPK-Mg fertilizer. On the basis of these results, the 75% dosage of NPK-Mg combined with 150 g of biochar per seed can be recommended for use on oil palm seedlings