Numerical Investigation of Helicopter Rotors in Ground Effect

Kutz, Benjamin; Kowarsch, Ulrich; Keßler, Manuel; Kraemer, Ewald

doi:10.2514/6.2012-2913

Cited by 14 publications

(9 citation statements)

References 12 publications

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“…7 shows a HELICOPTER in forward flight close to the ground. This simulation by Kutz et al [KKKK12] was used to study brown-out, i.e., the entrainment of sand particles by aerodynamic uplift and impacting particles. Brown-out clouds hinder the pilot's view and are mainly introduced by a vortex in front of the helicopter that is shown by the green surface.…”

Section: Resultsmentioning

confidence: 99%

Opacity Optimization for Surfaces

Günther¹,

Schulze²,

Esturo

et al. 2014

Computer Graphics Forum

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In flow visualization, integral surfaces rapidly tend to expand, fold and produce vast amounts of occlusion. While silhouette enhancements and local transparency mappings proved useful for semi‐transparent depictions, they still introduce visual clutter when surfaces grow more complex. An effective visualization of the flow requires a balance between the presentation of interesting surface parts and the avoidance of occlusions that hinder the view. In this paper, we extend the concept of opacity optimization to surfaces to obtain a global approach to the occlusion problem. Starting with a partition of the surfaces into patches, we compute per‐patch opacity as minimizer of a bounded‐variable least‐squares problem. For the final rendering, opacity is interpolated on the surfaces. The resulting visualization technique is interactive, frame‐coherent, view‐dependent and driven by domain knowledge.

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Section: Resultsmentioning

confidence: 99%

Opacity Optimization for Surfaces

Günther¹,

Schulze²,

Esturo

et al. 2014

Computer Graphics Forum

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show abstract

“…The second unsteady sequence captures the simulation of the flow regime around a helicopter in slow forward flight close to the ground. The data by Kutz et al [KKKK12] was studied for brown‐out conditions [GKKT13]. Fig.…”

Section: Resultsmentioning

confidence: 99%

Hierarchical opacity optimization for sets of 3D line fields

Günther¹,

Rössl²,

Theisel³

2014

Computer Graphics Forum

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Figure 1: View-dependent, frame-coherent and interactive selection of meaningful lines for sets of line fields: pathlines (left, 58 ms/opacity update) and streaklines (right, 78 ms/opacity update) in a cylinder flow. AbstractThe selection of meaningful lines for 3D line data visualization has been intensively researched in recent years. Most approaches focus on single line fields where one line passes through each domain point. This paper presents a selection approach for sets of line fields which is based on a global optimization of the opacity of candidate lines. For this, existing approaches for single line fields are modified such that significantly larger amounts of line representatives are handled. Furthermore, time coherence is addressed for animations, making this the first approach that solves the line selection problem for 3D time-dependent flow. We apply our technique to visualize dense sets of pathlines, sets of magnetic field lines, and animated sets of pathlines, streaklines and masslines. This is the authors preprint. The definitive version is available at

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“…The ICON simulation is part of the HD(CP) 2 project and was kindly provided by Heinze et al [25]. The flow around a HELICOPTER in slow forward flight close to the ground was provided by Kutz et al [32]. The TREFOIL data set was kindly provided by Candelaresi and Brandenburg [8].…”

Section: Acknowledgmentsmentioning

confidence: 99%

Fourier Opacity Optimization for Scalable Exploration

Rojo

Groß

Günther

2020

IEEE Trans. Visual. Comput. Graphics

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Over the past decades, scientific visualization became a fundamental aspect of modern scientific data analysis. Across all data-intensive research fields, ranging from structural biology to cosmology, data sizes increase rapidly. Dealing with the growing large-scale data is one of the top research challenges of this century. For the visual exploratory data analysis, interactivity, a view-dependent visibility optimization and frame coherence are indispensable. In this work, we extend the recent decoupled opacity optimization framework to enable a navigation without occlusion of important features through large geometric data. By expressing the accumulation of importance and optical depth in Fourier basis, the computation, evaluation and rendering of optimized transparent geometry become not only order-independent, but also operate within a fixed memory bound. We study the quality of our Fourier approximation in terms of accuracy, memory requirements and efficiency for both the opacity computation, as well as the order-independent compositing. We apply the method to different point, line and surface data sets originating from various research fields, including meteorology, health science, astrophysics and organic chemistry.

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Numerical Investigation of Helicopter Rotors in Ground Effect

Cited by 14 publications

References 12 publications

Opacity Optimization for Surfaces

Opacity Optimization for Surfaces

Hierarchical opacity optimization for sets of 3D line fields

Fourier Opacity Optimization for Scalable Exploration

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