Playback Robot Programming with Loop Increments

Playback robot programming is fast and easy to use for non-experts, because the robot only needs to be manually guided. However, it is only capable of replaying the trajectory exactly as it was taught. We present the concept of loop increments for playback programmed robots to allow the user to teach tasks like palletizing or stacking without having to explicitly guide the robot through each trajectory. Only the base trajectory for one repetition needs to be program med. After each loop iteration, the user-defined increment is added to the incremental configurations, e.g. to the pick or place configurations. To achieve this, two methods of defining the loop increments are shown. Afterwards, linear, Gaussian, and cosine blending functions in combination with the point and interval method are introduced for weighting the increments and as a foundation for the adaption algorithm. The evaluation showed, that the cosine blending function with the interval method best fits the needs of our programming system.

Numerical Resolution of Compressor Corner Separation Problem

Corner separation is a common flow phenomenon within compressors that can significantly affect the compressor performance. The RANS turbulence closures, commonly used in the industrial CFD simulations, often struggle to predict corner separation with reasonable accuracy. In this paper, the results of two RANS-based modelling approaches are presented for the corner separation within a high-loaded Prescribed Velocity Distribution (PVD) compressor cascade. The flow characteristics are studied to facilitate understanding the causes of varying performance of RANS models. It is observed that mixing plays a crucial role in accurately predicting the type, location, and size of flow separation. The source terms that control the turbulence mixing in SA and SST models are identified, based on physical analyses. Both RANS models are modified to better model the mixing process. Based on the modified SST model, an improved RANS-LES blending function has been proposed for a hybrid RANS-LES model. This new blending function ensures reliable shielding of attached boundary layers by the RANS portion of the hybrid model. Finally, to gain further understanding of the endwall flow physics, the turbulence characteristics of the resolved corner separation flow are studied, in terms of the large-scale unsteadiness and loss generation mechanisms.

Some Classes of Surfaces Generated by Blending Interpolation on a Triangle with One Curved Side

The blending interpolation has many practical applications. Remind that blending interpolation is to interpolate a function at an infinite set of points: segments, curves, surfaces, etc. Thus, if one gives the contour of an object by such elements (segments, curves, surfaces) using a blending interpolation, we can generate a surface that contains the given contour. Hence, we can construct a surface (a blending function interpolant) which matches a given function and certain on its derivatives on the boundary of a plane domain (rectangle, triangle, etc. The aim of this paper is to construct some surfaces which satisfy some given condition on the boundary of a domain that can be decomposed in triangles with one curved side. We construct some new surfaces using some Lagrange, Hermite, Birkhoff and Nielson type operators.

Modeling of Turbulent Swirl Stabilized Flame With Flamelet Generated Manifold and Hybrid LES-RANS Turbulence Model

Hybrid turbulence modeling is a practical approach to efficiently model the wall-bounded turbulent flows. In this paper, a stress-blended eddy simulation (SBES) model is used with the flamelet generated manifold model (FGM) for modeling turbulent combustion. In the current SBES, the near-wall region is modeled using a two-equation k-ω Reynolds-averaged Navier-Strokes (RANS) formulation, and switches to a large eddy simulation (LES) model in the core region using a blending function. Similarly, the turbulence-related combustion modeling parameters, such as the variances in scalar transport equations and scalar dissipation, are also blended using the same blending function. This combined hybrid FGM-SBES approach is implemented into ANSYS Fluent software and then used to model a swirl-stabilized flame. The flame used is a methane-fueled burner, developed at DLR Stuttgart as the PRECCINSTA combustor. The experimental data for this combustor are available for multiple operating conditions. A stable operating point (φ = 0.83, P = 30 kW) is chosen. The current FGM-SBES results are compared with experimental data as well as with FGM-LES computations. Differences in predictions of mean and variance of reaction progress and mixture fraction in the core versus the near wall region are analyzed and quantified. The impact of the differences in these parameters is then evaluated by comparing temperature and species mass fractions. The findings from the current work, in terms of accuracy, validity and best practices when modeling wall-bounded flows with FGM-SBES are discussed and summarized.

Conceptual Blending in Theatrical Performance

This project will be an examination of the potentialities of using conceptual blending to describe the cognitive processing that occurs when audience members engage in a theatrical event. Specifically, it will frame the processes using the play White Rabbit Red Rabbit by Nassim Soleimanpour, which itself examines the multiplicities of mental spaces required to engage in performance. In this project, I hope to examine conceptual blending and its relation to theatre, especially metatheatre, in which audience members must balance several levels of performance and reality in one theatrical event. There has been research conducted into relating blending theories with semantics, semiotics, and literature, in particular in the realm of metaphor in which a reader must maintain both the original and analogy in the same mental space in order to draw the comparison. The move towards theatre follows logically, as it encourages audiences to view a performance of fiction or imagination while balancing the 'real' quality of the actors, set pieces, or even words and story, as in verbatim and documentary performance, respectively. Considering these ideas, my core questions can be grouped around three main ideas: How does conceptual blending function when watching theatrical performance, specifically White Rabbit Red Rabbit? What specific moments in the script, performance, or audience experience in White Rabbit Red Rabbit prompt conceptual blending, or challenge our usual conceptual blending process? What implications are there for the use of conceptual blending or cognitive science in theatre for shaping audience perception?

Transitional Effect on Turbulence Model for Wind Turbine Blade

This paper presents the computational predictions of NREL Phase VI rotor using SST Gamma Theta turbulence model. All models were performed using the commercial CFD software, ANSYS Workbench CFX. Exactly the same geometry as NREL blades was built. Around 14 million unstructured mesh elements and 3.7 million nodes have been applied during the simulation. To deal with the boundary effect, 18 inflation layers were constructed around the boundary wall. The comparison of torque and thrust between several turbulent models and the experimental data were performed. For the overall performance, a better agreement with the NREL Experimental data was obtained with SST Gamma Theta model. After these verifications, the first, second SST blending function and transition blending function for seven distinct wind speeds were performed. It has been observed that SST Gamma Theta method can simulate the transition effect appropriately.

A modified blending function for zonal hybrid Reynolds-averaged Navier—Stokes/large-eddy simulation methodology

A modified blending function for zonal hybrid Reynolds averaged Navier—Stokes/large eddy simulation (RANS/LES) methodology was developed using an empirical analogy from Menter k—ω shear stress transport (SST) turbulent model (Menter, 1994) to predict complex turbulent flows. Tests of slot jet in supersonic flow and supersonic flow over compression—expansion ramp was conducted and prediction of separations was well improved when certain model constant was forced on the traditional blending function (Baurle et al., 2003). Analysis based on calculations of flat plate boundary layer demonstrated that an efficient empirical constant could be used in blending function and boundary layer could be well calculated without heavy contamination of RANS on wake region. Validation of the modified zonal hybrid RANS/LES approach for slot jet in supersonic flow, supersonic flow over compression—expansion ramp, supersonic flow over backward facing step, and supersonic cavity flow was conducted. The simulated results showed that the modified blending function performs well on complex turbulent flows. Deficiencies of traditional hybrid zonal RANS/LES method in over-prediction of separations associated with adverse pressure gradient flows were favourably improved.