The Role of CFD in Preliminary Aerospace Design (Keynote)

2003 ◽  
Author(s):  
Antony Jameson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Process ◽  
Design Problem ◽  
Development Project ◽  
Design Team ◽  
Aerodynamic Design ◽  
Trade Offs ◽  
Dynamics Analyses

This paper discusses the role that computational fluid dynamics plays in the design of aircraft. An overview of the design process is provided, covering some of the typical decisions that a design team addresses within a multi-disciplinary environment. On a very regular basis trade-offs between disciplines have to be made where a set of conflicting requirements exists. Within an aircraft development project, we focus on the aerodynamic design problem and review how this process has been advanced, first with the improving capabilities of traditional computational fluid dynamics analyses, and then with aerodynamic optimizations based on these increasingly accurate methods.

Discrete element method–computational fluid dynamics analyses of flexible fibre fluidization

2021 ◽  
Vol 910 ◽  
Author(s):  
Yiyang Jiang ◽  
Yu Guo ◽  
Zhaosheng Yu ◽  
Xia Hua ◽  
Jianzhong Lin ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Dynamics Analyses ◽  
Element Method

Abstract

Thermal Modeling of a Liquid-Cooled PM Traction Motor

2003 ◽  
Author(s):  
Edward Jih ◽  
Thomas Abraham ◽  
Stephen Stella ◽  
Roy Davis ◽  
Bert Dinger ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Permanent Magnet ◽  
Electric Motor ◽  
Hybrid Electric Vehicle ◽  
Effective Properties ◽  
Copper Wire ◽  
Critical Role ◽  
Traction Motor ◽  
Dynamics Analyses

The electric motor plays a critical role for the applications of the Hybrid Electric Vehicle and Fuel Cell Electric Vehicel. It is also well known that thermal constraints represent one of the main limitations in the performance of the electric motor. For example, the electric motor will be short-circuited if the insulation coatings of the copper wire bundles fail. Furthermore, the performance of the permanent magnet electric motor reduces significantly as the rotor magnet temperature increases. In this study, a series of Computational Fluid Dynamics analyses were performed for the design of a liquid-cooled permanent magnet electric motor to achieve better thermal performance. Several thermal tests of a partial permanent magnet traction motor assembly (stator and housing only) were also performed to determine effective properties of the stator slot and thermal contact resistance between stator and housing that may vary due to the manufacturing process. A simplified thermal network model of this system was established from the Computational Fluid Dynamics analyses. Then the critical heat transfer path of this system was identified.

Second Stage Optimization of Helical Groove Seals Using Computational Fluid Dynamics to Evaluate the Dependency of Optimized Design on Preswirl

2018 ◽  
Author(s):  
Cori Watson ◽  
Houston Wood
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Power Loss ◽  
Pressure Differential ◽  
Design Parameters ◽  
Working Fluid ◽  
Second Stage ◽  
Trade Offs ◽  
Helical Groove ◽  
Groove Seal

Helical groove seals are non-contacting annular seals used in pumping machinery to increase the efficiency and, in the case of the balance drum, to manage the axial force on the thrust bearing. Prior work has shown that optimization of helical groove seals can reduce the leakage by two thirds given a desired pressure differential or, conversely, can significantly increase the pressure differential across the helical groove seal given a flow rate. This study evaluates the dependency of the optimal helical groove seal design on the inlet preswirl, which is the ratio of the inlet circumferential velocity to the rotor surface speed. To accomplish this goal, second stage optimization from the previously optimized helical groove seal with grooves on the stator and water as the working fluid were conducted at a series of preswirls ranging from −1 to 1. Optimization is performed using ANSYS CFX, a commercial computational fluid dynamics software and mesh independence is confirmed for the baseline case. For each preswirl case, design of experiments for the design parameters of groove width, groove depth, groove spacing, and number of grooves was performed using a Kennard-Stone Algorithm. The optimized solution is interpolated from the simulations run by using multi-factor quadratic regression from the 30 simulations in each optimization and the interpolated solution is simulated for comparison. In addition to evaluating the optimized solution’s dependency on preswirl, the viability of using swirl breaks or swirl promoting inlet passages to improve the overall efficiency of the seal is discussed. Finally, the power loss performance is evaluated for each of the seal designs simulated so that potential trade-offs can be evaluated. Overall, the results show that increasing preswirl can increase the efficiency of the helical groove seal both by improving power loss and by improving leakage.

scholarly journals Remoras pick where they stick on blue whales

2020 ◽  
Vol 223 (20) ◽  
pp. jeb226654
Author(s):  
Brooke E. Flammang ◽  
Simone Marras ◽  
Erik J. Anderson ◽  
Oriol Lehmkuhl ◽  
Abhishek Mukherjee ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Experimental Work ◽  
Ecological Monitoring ◽  
Video Recordings ◽  
Venturi Effect ◽  
Separating Flow ◽  
Dynamics Analyses ◽  
Blue Whales

ABSTRACTAnimal-borne video recordings from blue whales in the open ocean show that remoras preferentially adhere to specific regions on the surface of the whale. Using empirical and computational fluid dynamics analyses, we show that remora attachment was specific to regions of separating flow and wakes caused by surface features on the whale. Adhesion at these locations offers remoras drag reduction of up to 71–84% compared with the freestream. Remoras were observed to move freely along the surface of the whale using skimming and sliding behaviors. Skimming provided drag reduction as high as 50–72% at some locations for some remora sizes, but little to none was available in regions where few to no remoras were observed. Experimental work suggests that the Venturi effect may help remoras stay near the whale while skimming. Understanding the flow environment around a swimming blue whale will inform the placement of biosensor tags to increase attachment time for extended ecological monitoring.

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