Large Eddy Simulation Investigation of the Hysteresis Effects in the Flow Around an Oscillating Ground Vehicle

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Siniša Krajnović ◽  
Anders Bengtsson ◽  
Branislav Basara
Keyword(s):  
Vertical Axis ◽  
The Body ◽  
Experimental Investigations ◽  
Flow Conditions ◽  
Ground Vehicle ◽  
The Road ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Mechanisms ◽  
On The Road

This paper presents large eddy simulations (LES) of flow around a simplified vehicle model oscillating around its vertical axis. The frequency of the Strouhal number St = 0.068 and a relatively small amplitude of the oscillation are chosen to be representative for the crosswind conditions of vehicles on the road. The results were found to agree well with data from previous experimental investigations. Furthermore, the differences in LES flows between quasi-steady and dynamic flow conditions are presented and underlying flow mechanisms are explored. The cause of the phenomena of hysteresis and phase shift was found in the inertia of the flow to adjust to sudden changes in the direction of the oscillation of the body.

Flow Around a Simplified Car, Part 1: Large Eddy Simulation

2005 ◽  
Vol 127 (5) ◽  
pp. 907-918 ◽  
Author(s):  
Siniša Krajnović ◽  
Lars Davidson
Keyword(s):  
Reynolds Number ◽  
The Body ◽  
Ground Vehicle ◽  
Surface Separation ◽  
Recirculating Flow ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Number Effects ◽  
Sharp Edges ◽  
High Reynolds

Large eddy simulations (LES) were made of flows around a generic ground vehicle with sharp edges at the rear end (an Ahmed body with a 25° angle of the rear slanted surface). Separation of the flow at the rear results in large regions with recirculating flow. As the separation is determined by the geometry, the Reynolds number effects are minimized. Resolution requirements of this recirculating flow are smaller than those in LES of wall attached flows. These two consequences of the geometry of the body are used to predict the experimental flow at relatively high Reynolds number. Recommendations are presented for the preparation and realization of LES for vehicle flows. Comparison of the LES results with the experimental data shows good agreement.

scholarly journals Load Measurement of the Cervical Vertebra C7 and the Head of Passengers of a Car While Driving Across Uneven Terrain

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3849
Author(s):  
Martin Svoboda ◽  
Milan Chalupa ◽  
Karel Jelen ◽  
František Lopot ◽  
Petr Kubový ◽  
...  
Keyword(s):  
Cervical Vertebrae ◽  
Vertical Direction ◽  
Cervical Vertebra ◽  
Parietal Bone ◽  
The Body ◽  
Human Organism ◽  
Dynamic Effects ◽  
The Road ◽  
Real Environment ◽  
On The Road

The article deals with the measurement of dynamic effects that are transmitted to the driver (passenger) when driving in a car over obstacles. The measurements were performed in a real environment on a defined track at different driving speeds and different distributions of obstacles on the road. The reaction of the human organism, respectively the load of the cervical vertebrae and the heads of the driver and passenger, was measured. Experimental measurements were performed for different variants of driving conditions on a 28-year-old and healthy man. The measurement’s main objective was to determine the acceleration values of the seats in the vehicle in the vertical movement of parts of the vehicle cabin and to determine the dynamic effects that are transmitted to the driver and passenger in a car when driving over obstacles. The measurements were performed in a real environment on a defined track at various driving speeds and diverse distributions of obstacles on the road. The acceleration values on the vehicle’s axles and the structure of the driver’s and front passenger’s seats, under the buttocks, at the top of the head (Vertex Parietal Bone) and the C7 cervical vertebra (Vertebra Cervicales), were measured. The result of the experiment was to determine the maximum magnitudes of acceleration in the vertical direction on the body of the driver and the passenger of the vehicle when passing a passenger vehicle over obstacles. The analysis of the experiment’s results is the basis for determining the future direction of the research.

scholarly journals Two-Layer Routing for High-Voltage Powerline Inspection by Cooperated Ground Vehicle and Drone

2019 ◽  
Author(s):  
Yao Liu ◽  
Jianmai Shi ◽  
Zhong Liu ◽  
Jincai Huang ◽  
Tianren Zhou
Keyword(s):  
High Voltage ◽  
Road Network ◽  
Inspection System ◽  
Large Area ◽  
Technical Improvement ◽  
Routing Problem ◽  
Ground Vehicle ◽  
The Road ◽  
Battery Capacity ◽  
On The Road

A novel high-voltage powerline inspection system is investigated, which consists of the cooperated ground vehicle and drone. The ground vehicle acts as a mobile platform that can launch and recycle the drone, while the drone can fly over the powerline for inspection within limited endurance. This inspection system enables the drone to inspect powerline networks in a very large area. Both vehicle’ route in the road network and drone’s routes along the powerline network have to be optimized for improving the inspection efficiency, which generates a new two-layer point-arc routing problem. Two constructive heuristics are designed based on “Cluster First, Rank Second” and “Rank First, Split Second”. Then local search strategies are developed to further improve the quality of the solution. To test the performance of the proposed algorithms, practical cases with different-scale are designed based on the road network and powerline network of Ji’an, China. Sensitivity analysis on the parameters related with the drone’s inspection speed and battery capacity is conducted. Computational results indicate that technical improvement on the inspection sensor is more important for the cooperated ground vehicle and drone system.

Grasshopper theology: Heading to the Promised Land instead of climate disaster

2018 ◽  
Vol 115 (3) ◽  
pp. 412-416
Author(s):  
Brooks Berndt
Keyword(s):  
The Body ◽  
Body Of Christ ◽  
Self Assessment ◽  
The Road ◽  
Promised Land ◽  
The Future ◽  
The Face ◽  
On The Road ◽  
Uncertain Future ◽  
Climate Crisis

Today’s climate crisis provokes dystopian and utopian narratives of the future faced by humanity. To navigate the theological terrain between the present and an uncertain future, this article explores passages pertaining to the journey of Moses and the Israelites to the Promised Land. The guiding point of orientation for this exploration comes from a verse that captures the seeming powerlessness of the Israelites in the face of the giants inhabiting the Promised Land. Numbers 13:33 reads, “To ourselves we seemed like grasshoppers, and so we seemed to them.” Of crucial importance in coming to terms with such honest self-assessment is the period of discernment and growth that comes from being in the wilderness with the presence of a God who loves and empowers grasshoppers in the face of seemingly insurmountable odds. Because the future of the Body of Christ is inseparable from how the climate crisis is confronted, the journey through the wilderness becomes not merely a story for self-coping but rather a story about churches finding a way forward, even as some dystopian narratives place churches on the road to irrelevance and ultimately extinction. This article explores how the story of exodus provides a sacred ground for imagining a different, even if difficult, future.

Reforming child welfare: Diverting by-ways on the road to utopia?

1985 ◽  
Vol 18 (4) ◽  
pp. 237-256 ◽  
Author(s):  
Terry Carney
Keyword(s):  
Child Welfare ◽  
Social Policy ◽  
The Body ◽  
Main Theme ◽  
Free Standing ◽  
The Road ◽  
Existing Structures ◽  
Australian State ◽  
Significant Area ◽  
On The Road

This article, written from a less than detached standpoint by the chairperson of the body concerned, takes the recently completed review of child welfare practice and legislation in the Australian State of Victoria, as a case study of the contours, and of the factors which shape, law reform in areas of social policy. Substantive issues dealt with in the body of the Report1 will not be addressed here. Rather, the article considers some of the reasons which might explain why the task was not entrusted to one of the existing structures for the review of law and social policy in this State, and it canvasses some of the features which may make review by such a free-standing committee the preferred approach when reviewing social policy. The main theme to be explored is that of the role of reviews in accelerating (or inhibiting) the process of change in a legal, welfare practice and public policy context. To this end the article addresses such matters as: the significance of the composition of the review body; its techniques of consultation with the public and with government; its dealings with government and major centres of power; and related matters which bear on its capacity to discharge its basic mandate. The contextual pressures which favour system inertia, or which may transform reform measures into something other than what was intended by the proponents of change, will also be alluded to. It will be argued that the model of expert independent committee suffers from a vulnerability to the effects of external factors and relationships. These may leach away much of its capacity to undertake a thorough, detached evaluation of its specified field, and preclude it from building up significant momentum for change. Nevertheless, it is contended that these weak points are capable of being shored up. As a consequence it is concluded that this model is superior to its competitors when a significant area of social policy is thought to be ripe for evaluation and change.

Air-Car

2005 ◽  
Author(s):  
Mahmood Anwar
Keyword(s):  
Lift Force ◽  
Third World ◽  
Large Scale ◽  
Ground Level ◽  
The Body ◽  
Stream Line ◽  
Traffic Jam ◽  
Traffic System ◽  
The Road ◽  
On The Road

The name of my proposing project is “air-car”. Now a day’s traffic jam is common problem of the mega city, especially in third world countries. so, if we design the traffic system such that the light vehicles like car will flies over certain height from the ground level about 100-200 ft and the heavy vehicle like bus, truck, lorry, etc. will run on the road simultaneously then the traffic jam will be minimize with a large scale. Let us introduce with the concept “air-car”. Air car is the vehicle which can run in both way of air and road. That means that it can fly over a certain height from the ground and also run in the road as usual. We know that for the car design is such the lift force is minimized than the drag force. I want to design for the car such that, when the car has to fly lift force will be increase as much as it can fly for the required height. The body of the car also be a stream line body and the flap, aileron, rudder also be added. But this should be hidden at the time of running in the road.

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