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The predictive capabilities of blade-resolved unsteady Reynolds averaged Navier-Stokes (URANS) and detached eddy simulation (DES), the most commonly used hybrid RANS/large eddy simulation (LES) model, are assessed for hydrokinetic turbine performance and mean and turbulent flows in the intermediate-wake region, and results for a range of tip-speed ratio encompassing design and off-design conditions are analyzed to understand the wake recovery mechanism. The performance predictions compared within 5% of the experimental data. Both URANS and DES models performed reasonably well for the near wake predictions, where the errors were

Background: Information is needed regarding the complex relationships between long-term functional outcomes and health-related quality of life (HRQoL) in Hirschsprung's Disease (HSCR). We describe longterm outcomes across multiple domains, completing a core outcome set through to adulthood. Methods: HSCR patients operated at a single center over a 35-year period (1978-2013) were studied. Patients completed detailed questionnaires on bowel and urologic function, and HRQOL. Patients with learning disability (LD) were excluded. Outcomes were compared to normative data. Data are reported as median [IQR] or mean (SD). Results: 186 patients (median age 28 [18-32] years; 135 males) completed surveys. Bowel function was reduced (BFS 17 [14-19] vs. 19 [19-20], p < 0.0001;eta(2) = 0.22). Prevalence and severity of fecal soiling and fecal awareness improved with age ( p < 0.05 for both). Urinary incontinence was more frequent than controls, most of all in 13-26y females (65% vs. 31%, p = 0.003). In adults, this correlated independently with constipation symptoms (OR 3.18 [1.4-7.5], p = 0.008). HRQoL outcomes strongly correlated with functional outcome: 42% of children demonstrated clinically significant reductions in overall PedsQL score, and poor bowel outcome was strongly associated with impaired QOL (B = 22.7 [12.7- 32.7], p < 0.001). In adults, GIQLI scores were more often impacted in patients with extended segment disease. SF-36 scores were reduced relative to population level data in most domains, with large effect sizes noted for females in General Health (g = 1.19) and Social Wellbeing (g = 0.8). Conclusion: Functional impairment is common after pull-through, but bowel function improves with age. Clustering of poor functional outcomes across multiple domains identifies a need for early recognition and long-term support for these patients. (C) 2021 Elsevier Inc. All rights reserved.

The solution to many engineering problems is obtained through the combination of analytical, computational and experimental methods. In many cases, cost or size constraints limit testing of full-scale articles. Similitude allows observations made in the laboratory to be used to extrapolate the behavior to full-scale system by establishing relationships between the results obtained in a scaled experiment and those anticipated for the full-scale prototype. This paper describes the application of the Buckingham Pi theorem to develop a set of non-dimensional parameters that are appropriate for describing the problem of a distributed load applied to the rostrum of the paddlefish. This problem is of interest because previous research has demonstrated that the rostrum is a very efficient structural system. The ultimate goal is to estimate the response of a complex, bio-inspired structure based on the rostrum to blast load. The derived similitude laws are verified through a series of numerical experiments having a maximum error of 3.39%.

Bio-structures have been optimized by nature to possess remarkable resiliency and strength yet retain a light-weight composition. The hierarchical geometrical arrangements that are prevalent in bio-structures, coupled with heterogeneous constituents, present uncertainty as to what dictates the structural response. Although computational mechanics experiments give an overall distribution of stresses in the structural system, the underlying details of the stress flow patterns in the structure are hard to identify. This paper discusses the development of software that integrates the results from computational mechanics experiments with advanced mathematical algorithms to capture the stress distribution in a bio-structure subjected to an external load. A fundamental issue addressed in this work is the procedure used to prepare data in appropriate format for the seamless transition from finite element binary database files to an abstract mathematical domain. The robust, platform-independent procedure developed for this transdisciplinary strategy efficiently handles the large datasets produced by the high performance computational mechanics experiments.

In this paper, we revisit the Lagrangian accumulation process that aggregates the local attribute information along integral curves for vector field visualization. Similar to the previous work, we adopt the notation of the Lagrangian accumulation field or A field for the representation of the accumulation results. In contrast to the previous work, we provide a more in-depth discussion on the properties of A fields and the meaning of the patterns exhibiting in A fields. In particular, we revisit the discontinuity in the A fields and provide a thorough explanation of its relation to the flow structure and the additional information about the flow that it may reveal. In addition, other remaining questions about the A field, such as its sensitivity to the selection of integration time, are also addressed. Based on these new insights, we demonstrate a number of enhanced flow visualizations aided by the accumulation framework and the A fields, including a new A field guided ribbon placement, an A field guided stream surface seeding and the visualization of particle-based flow data. To further demonstrate the generality of the accumulation framework, we extend it to the non-integral geometric curves (i.e., streak lines), which enable us to reveal information about the flow behavior other than those revealed by the integral curves. Finally, we introduce the Eulerian accumulation, which can reveal different flow behaviors than those revealed by Lagrangian accumulation. In summary, we believe that Lagrangian accumulation and the resulting A fields offer a valuable means to investigate flow behavior complementary to the current state-of-the-art techniques.

A new strategy for simulating the flow around iced airfoils is presented in this paper. Two different approaches are used to generate quality grids over the iced airfoil. Both grids can be categorized as generalized grids since multiple element types are employed in each. In the first approach, a structured grid is generated near the body using a marching scheme and the rest of the domain is filled with an unstructured grid. In the second approach, the marching strategy is coupled with a node deletion/insertion algorithm to generate a quad-dominant grid. An edge based data structure is used to store the grid information to handle polygons with an arbitrary number of sides. A finite-volume, cell-centered scheme is used to solve the integral form of the full Navier-Stokes equations. The numerical fluxes crossing the cellfaces are calculated using Roe's approximate Riemann solver. The turbulent viscosity is estimated using Spalart-Allmaras one equation turbulence model. The results of computations are presented, together with comparison to NPARC results.

During pressure testing of a downhole plugging tool manufactured from a duplex stainless steel forging, a failure occurred that had not been observed in similar development projects. The failure was characterised by surface pinhole formation and cracking associated with a region of high plastic strain. Examination revealed that the defects were associated with areas of σ-phase at the ferrite/austenite phase boundaries local to the centre of the 250 mm diameter forging. Estimation of the cooling rates of the forging during oil quenching showed that the centre region of the forging would not cool at a rate sufficient to exceed the critical cooling rate for σ-phase formation. The material was shown to be capable of withstanding greater levels of plastic strain in regions where no σ-phase existed.

Solution adaptive grid strategies based on the redistribution of a fixed number of points are described in this paper. The redistribution is performed using weight functions that vary based on significant flow features. The weight functions are evaluated using an equidistribution principle. In this paper, emphasis is placed on the development of weight functions applicable to compressible flows exhibiting large scale separated vortical flows, vortex‐vortex and vortex‐surface interactions, separated shear layers and multiple shocks of diAerent intensities. Algebraic, elliptic and parabolic methods of grid generation have been utilized for structured grid redistribution. Additionally, a point movement scheme is presented for generalized (structured/unstructured/hybrid) grid adaptation. Computer Aided Geometry Design (CAGD) techniques are combined with redistribution schemes to maintain the fidelity of solid boundaries. In particular, solid boundaries are represented using Non-Uniform Rational B-Splines (NURBS). A grid generation software system ‐ Parallel Multiblock Adaptive Grid generation (PMAG) ‐ using an elliptic redistribution scheme is also described with emphasis placed on the parallel implementation for multiblock structured grids with unstructured blocking topologies and on interpolation issues. Computational examples demonstrating the influence of diAerent weight functions and grid redistribution strategies are presented. ” 2000 Elsevier Science S.A. All rights reserved.