Modeling of Air Flow Over a Generic Aircraft Carrier With and Without Island Structure

2021 ◽  
Vol 163 (A3) ◽  
Author(s):  
MP Mathew ◽  
SN Singh ◽  
SS Sinha ◽  
R Vijayakumar
Keyword(s):  
Automobile Industry ◽  
Quantitative Estimation ◽  
Forward Direction ◽  
Open Domain ◽  
Aircraft Carrier ◽  
Carrier Model ◽  
Numerical Studies ◽  
The World ◽  
External Aerodynamics ◽  
Flight Deck

The study of external aerodynamics of an aircraft carrier is of utmost importance in ensuring the safety of aircraft and pilots during take-off and recovery. The velocity deficit in the forward direction and the downwash together combine to give a sinking effect to the aircraft, along its glideslope path and is known as the ‘burble’ in naval aviation parlance. This phenomenon is primarily responsible for the potential increase in pilot workload on approach to the aircraft carrier. There is little literature in the open domain regarding ways and means to alleviate the burble effect. Unlike in the case of the automobile industry, which has the generic ‘Ahmed body’ and for the frigates/destroyers, for which there is the Simplified Frigate Ship (SFS), on which experiments and validation through CFD could be carried out, by researchers from all over the world, there is no generic Aircraft Carrier model for carrying out experiments and validation of CFD codes. The aim of this study is to define the Generic Aircraft Carrier Model (GAC), as developed at IIT Delhi, and to carry out numerical studies on the GAC and a variant of GAC without the island, BGAC (Baseline GAC), to assess the contribution of the island to the burble behind an Aircraft Carrier. This study gives a quantitative estimation of the effect and contribution of individual components of an Aircraft Carrier (like flight deck, island, etc.) to the burble behind the carrier, and would give a Naval Ship Designer an understanding of the effect of the geometrical configuration of the flight deck and the island on generation of the burble behind the carrier, which could aid the designer in potentially reducing the pilot workload.

scholarly journals An Extended Flexible Job Shop Scheduling Model for Flight Deck Scheduling with Priority, Parallel Operations, and Sequence Flexibility

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Lianfei Yu ◽  
Cheng Zhu ◽  
Jianmai Shi ◽  
Weiming Zhang
Keyword(s):  
Differential Evolution ◽  
Job Shop ◽  
Job Shop Scheduling ◽  
Time Budget ◽  
Differential Evolution Algorithm ◽  
Mixed Integer ◽  
Aircraft Carrier ◽  
Evolution Algorithm ◽  
Improved Differential Evolution Algorithm ◽  
Flight Deck

Efficient scheduling for the supporting operations of aircrafts in flight deck is critical to the aircraft carrier, and even several seconds’ improvement may lead to totally converse outcome of a battle. In the paper, we ameliorate the supporting operations of carrier-based aircrafts and investigate three simultaneous operation relationships during the supporting process, including precedence constraints, parallel operations, and sequence flexibility. Furthermore, multifunctional aircrafts have to take off synergistically and participate in a combat cooperatively. However, their takeoff order must be restrictively prioritized during the scheduling period accorded by certain operational regulations. To efficiently prioritize the takeoff order while minimizing the total time budget on the whole takeoff duration, we propose a novel mixed integer liner programming formulation (MILP) for the flight deck scheduling problem. Motivated by the hardness of MILP, we design an improved differential evolution algorithm combined with typical local search strategies to improve computational efficiency. We numerically compare the performance of our algorithm with the classical genetic algorithm and normal differential evolution algorithm and the results show that our algorithm obtains better scheduling schemes that can meet both the operational relations and the takeoff priority requirements.

scholarly journals A Retrospective Look at Rescuing and Restructuring General Motors and Chrysler

2015 ◽  
Vol 29 (2) ◽  
pp. 3-24 ◽  
Author(s):  
Austan D. Goolsbee ◽  
Alan B. Krueger
Keyword(s):  
Automobile Industry ◽  
Decision Process ◽  
General Motors ◽  
Difficult Decision ◽  
Industrial Companies ◽  
Us Economy ◽  
The Us ◽  
Look Back ◽  
The World ◽  
Us Government

The rescue of the US automobile industry amid the 2008–2009 recession and financial crisis was a consequential, controversial, and difficult decision made at a fraught moment for the US economy. Both of us were involved in the decision process at the time, but since have moved back to academia. More than five years have passed since the bailout began, and it is timely to look back at this unusual episode of economic policymaking to consider what we got right, what we got wrong, and why. In this article, we describe the events that brought two of the largest industrial companies in the world to seek a bailout from the US government, the analysis that was used to evaluate the decision (including what the alternatives were and whether a rescue would even work), the steps that were taken to rescue and restructure General Motors and Chrysler, and the performance of the US auto industry since the bailout. We close with general lessons to be learned from the episode.

Flight Deck Design of the Next Generation Aircraft Carrier

2000 ◽  
Vol 112 (3) ◽  
pp. 69-75 ◽  
Author(s):  
W. Baker ◽  
S. D. Brennan ◽  
M. Husni
Keyword(s):  
Next Generation ◽  
Aircraft Carrier ◽  
Flight Deck Design ◽  
Flight Deck

Optimization of a columnar vortex generator installed over an aircraft carrier ski-jump ramp

2019 ◽  
Vol 234 (1) ◽  
pp. 223-230
Author(s):  
Rafael Bardera
Keyword(s):  
Vortex Generator ◽  
Wind Tunnel Testing ◽  
Low Velocity ◽  
Aircraft Carrier ◽  
Recirculation Bubble ◽  
Columnar Vortex ◽  
Flow Disturbances ◽  
Image Velocimetry ◽  
Field Velocity ◽  
Flight Deck

Aircraft performances over aircraft carriers are essential in modern navies. Take-off operation is critical due to the short runway available. The ski-jump ramp is a useful system that allows to operate under safe conditions. However, the sharp edge at the end of the runway provokes a region with recirculation bubble and low velocity producing strong flow disturbances. Hence, the aircraft performances are affected and the pilot’s workload is augmented. Previous researches showed that columnar vortex generator reduces the recirculation bubble generated over the end of flight deck. This article presents an in-depth experimental study performed by wind tunnel testing in order to determine the relation between the columnar vortex generator size and the recirculation bubble reduction. Particle image velocimetry is used to investigate the flow field velocity and flow structure around the ski-jump ramp as a non-intrusive experimental technique. Encouraging results were found for the biggest columnar vortex generator studied.

A Statistical Analysis on Automobile Sales Performance in India

2020 ◽  
Vol 17 (2) ◽  
pp. 778-782
Author(s):  
Kayalvizhi Subramanian ◽  
Mahmod Othman ◽  
Rajalingam Sokkalingam ◽  
Gunasekar Thangarasu
Keyword(s):  
Statistical Analysis ◽  
Automobile Industry ◽  
Sales Performance ◽  
Sales Growth ◽  
Export Markets ◽  
Secondary Sources ◽  
The Past ◽  
The World ◽  
Automobile Sales ◽  
Performance Report

The automobile business is a main drivers of India’s economy and also one of the biggest markets in the world. The automobile business has developed more grounded in deals over all fragments have been record breaking number in the past in both domestic and export markets. The presence of many manufacturers and brands in the country provides many choices to the buyers. This study pursues to examine the sales of the Indian Automobile Industry through statistical methods. The data used in this analysis are from secondary sources. The period of the study spans from 2012–2018. The obtained result shows on positive sales growth in the past five years. The automobile sales performance report will be useful for the current and new participant vehicle fabricating organization in India.

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