scholarly journals Reduction of Drag Resistance by Pressure Drop in Pipeline with 3-Dimensional Design Optimization

2021 ◽  
Vol 83 (2) ◽  
pp. 44-53
Author(s):  
Gunawan ◽  
Allessandro Setyo Anggito Utomo ◽  
F. Fariz ◽  
S. A. Lambang
Keyword(s):  
Pressure Drop ◽  
Drag Reduction ◽  
Design Optimization ◽  
Reduction Rate ◽  
Dijkstra’S Algorithm ◽  
3 Dimensional ◽  
Dijkstra's Algorithm ◽  
Number Of Bends ◽  
Pipeline Design ◽  
Dimensional Mapping

The searching for the most optimal pipeline route is a crucial problem in the maritime world because it consumes total designing time by 50%. Also, with different types of ships increases the design complexity. The usual design process has not considered the aspect of distance, cost, obstacles, drag, and pressure reduction in the pipeline very accurately. However, along with algorithms' development to optimize pipeline design, the time can be cut by 40%. This research uses computer-generated Dijkstra's algorithm to optimize pipeline design by considering several constraints in pipe spacing, the number of bends, crossings, pipeline stacks to improve drag reduction, and reducing pressure. This research was conducted to see the effect of pipe mapping on pressure drop, which is too influenced by human decisions that cannot consider bending, crossing, pipe piling, and bending of pipes that are too many to be considered by humans. Helping humans choose pipe mappings with various considerations that can affect pressure drop is advantageous because mapping helps to cut production times and produce a more efficient flow. In this study, this research aims to produce pressure drop by mapping pipes using the Djikstra algorithm by considering bending, crossing, and stacking, which are presented based on the 2-dimensional and 3-dimensional mapping. The data generated in the way of a comparison between drag reduction and pressure drop in pipe design optimization utilizing Dijkstra's and without using the Dijkstra's algorithm with 3-dimensional projections. The result shows the improvement of the drag reduction rate by 8% by decreasing pressure drop by 13%.

Pressure drop and drag reduction in two-phase non-newtonian slug flow

1976 ◽  
Vol 54 (1-2) ◽  
pp. 111-114 ◽  
Author(s):  
Lambert Otten ◽  
Abdelrahman S. Fayed
Keyword(s):  
Pressure Drop ◽  
Drag Reduction ◽  
Slug Flow ◽  
Two Phase

scholarly journals Numerical Investigation of an Optimized Rotor Head Fairing for the RACER Compound Helicopter in Cruise Flight

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Patrick Pölzlbauer ◽  
Andreas Kümmel ◽  
Damien Desvigne ◽  
Christian Breitsamter
Keyword(s):  
Drag Reduction ◽  
Design Optimization ◽  
Cost Effective ◽  
Aerodynamic Design ◽  
Ansys Fluent ◽  
Aerodynamic Design Optimization ◽  
Flow Phenomena ◽  
Compound Helicopter ◽  
Rotor Head ◽  
Cruise Flight

The present work is part of the Clean Sky 2 project Full-Fairing Rotor Head Aerodynamic Design Optimization (FURADO), which deals with the aerodynamic design optimization of a full-fairing rotor head for the Rapid And Cost-Effective Rotorcraft (RACER) compound helicopter. The rotor head is a major drag source and previous investigations have revealed that the application of rotor head fairings can be an effective drag reduction measure. As part of the full-fairing concept, a new blade-sleeve fairing was aerodynamically optimized for cruise flight. Within this publication, the newly developed blade-sleeve fairing is put to test on an isolated, five-bladed rotor head and compared to an already existing reference blade-sleeve fairing, which was developed at Airbus Helicopters. Numerical flow simulations are performed with ANSYS Fluent 2019 R2 considering a rotating rotor head with cyclic pitch movement. The aerodynamic forces of the isolated rotor head are analyzed to determine the performance benefit of the newly developed blade-sleeve fairing. A drag reduction of 4.7% and a lift increase of 20% are obtained in comparison to the Airbus Helicopters reference configuration. Furthermore, selected surface and flow field quantities are presented to give an overview on the occurring flow phenomena.

scholarly journals Railway timetabling: a maximum bottleneck path algorithm for finding an additional train path

2020 ◽  
Author(s):  
Fredrik Ljunggren ◽  
Kristian Persson ◽  
Anders Peterson ◽  
Christiane Schmidt
Keyword(s):  
Experimental Evaluation ◽  
Temporal Distance ◽  
Dijkstra’S Algorithm ◽  
Passenger Traffic ◽  
Dijkstra's Algorithm ◽  
Railway Timetabling

Abstract We present an algorithm to insert a train path in an existing railway timetable close to operation, when we want to affect the existing (passenger) traffic as little as possible. Thus, we consider all other trains as fixed, and aim for a resulting train path that maximizes the bottleneck robustness, that is, a train path that maximizes the temporal distance to neighboring trains in the timetable. Our algorithm is based on a graph formulation of the problem and uses a variant of Dijkstra’s algorithm. We present an extensive experimental evaluation of our algorithm for the Swedish railway stretch from Malmö to Hallsberg. Moreover, we analyze the size of our constructed graph.

scholarly journals Global effect of local skin friction drag reduction in spatially developing turbulent boundary layer

2016 ◽  
Vol 805 ◽  
pp. 303-321 ◽  
Author(s):  
A. Stroh ◽  
Y. Hasegawa ◽  
P. Schlatter ◽  
B. Frohnapfel
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Drag Reduction ◽  
Control Region ◽  
Reduction Rate ◽  
Wall Turbulence ◽  
Local Skin ◽  
Control Schemes ◽  
Local Skin Friction ◽  
Friction Drag Reduction

A numerical investigation of two locally applied drag-reducing control schemes is carried out in the configuration of a spatially developing turbulent boundary layer (TBL). One control is designed to damp near-wall turbulence and the other induces constant mass flux in the wall-normal direction. Both control schemes yield similar local drag reduction rates within the control region. However, the flow development downstream of the control significantly differs: persistent drag reduction is found for the uniform blowing case, whereas drag increase is found for the turbulence damping case. In order to account for this difference, the formulation of a global drag reduction rate is suggested. It represents the reduction of the streamwise force exerted by the fluid on a plate of finite length. Furthermore, it is shown that the far-downstream development of the TBL after the control region can be described by a single quantity, namely a streamwise shift of the uncontrolled boundary layer, i.e. a changed virtual origin. Based on this result, a simple model is developed that allows the local drag reduction rate to be related to the global one without the need to conduct expensive simulations or measurements far downstream of the control region.

scholarly journals Predictors of Success in Ablation of Scar-Related Ventricular Tachycardia

2013 ◽  
Vol 7 ◽  
pp. CMC.S11501 ◽  
Author(s):  
Mazen T. Ghanem ◽  
Rania S. Ahmed ◽  
Ayman M. Abd El Moteleb ◽  
John K. Zarif
Keyword(s):  
Ventricular Tachycardia ◽  
Univariate Analysis ◽  
Scar Tissue ◽  
Focal Lesions ◽  
3 Dimensional ◽  
Linear Lesions ◽  
Linear Ablation ◽  
Dimensional Mapping ◽  
Mapping Systems

During ablation of re-entrant ventricular tachycardia (VT) 3-dimensional mapping systems are now used to properly delineate the scar tissue and aid ablation of scar-related VT. The aim of our study was to outline how the mode of ablation predicts success and recurrence in large scar-related VT. When comparing patients with recurrence and patients with no recurrence, univariate analysis showed that number of ablation lesions (28 ± 8 vs. 12 ± 8, P = 0.01) and more linear ablation lesions rather than focal lesions ( P = 0.03) were associated with long-term success. We demonstrated that more extensive ablation lesions and creation of linear lesions is associated with better success rate and lower recurrence rate during ablation of large scar-related ventricular tachycardia.

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