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Article
Publication date: 23 June 2021

Mohammad Mehdi Razzaghi

This study aims to present a moving grid method based on the manipulation of connections.

Abstract

Purpose

This study aims to present a moving grid method based on the manipulation of connections.

Design/methodology/approach

In this study, the grid’s connections were manipulated to simulate a released store’s displacement. The selected model in this research is the EGLIN test case. In the introduced method, connections are modified in specific nodes of the grid. Governing flow equations were solved with the finite volume method. The major characteristic of this technique is using the averaging method for calculating the flux of cells.

Findings

This method maintains the grid’s quality even in large displacements of the released store. The three-dimensional simulation was carried out in transonic and supersonic regimes. Comparison of the results with experimental data were highly satisfactory.

Research limitations/implications

Using this moving grid method is recommended for simulating other models.

Practical implications

Prediction of store trajectory released from air vehicles is one of the most critical issues under study especially in the design of new stores.

Originality/value

The most prominent advantage of this method is maintaining the grid quality simultaneous with large displacements of the released store.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 5
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 October 2000

Stephen J. Pinchak and Asok Ray

The goal of the paper is to present an enhancement of the existing on‐board ground collision avoidance system (GCAS) that is designed to increase pilot safety in USAF A‐10…

Abstract

The goal of the paper is to present an enhancement of the existing on‐board ground collision avoidance system (GCAS) that is designed to increase pilot safety in USAF A‐10 aircraft. The A‐10 is a single‐seat, twin‐engine aircraft with a 30mm, seven‐barreled Gatling gun and 11 weapon pylons designed to fly at low level in close air support missions. The GCAS system provides both visual and aural cues for a pilot‐initiated recovery. The proposed algorithm of GCAS enhancement is built on a simple linear regression model that predicts the recovery height of the aircraft following a warning call and allows pilots to compare their own training events with flight test standards. This paper presents a discussion of model development, validation and comparison of the model predictions with actual flight test events. A comparison of recovery techniques and pilot options is included. A series of recommendations and possible usage for Air Force pilot training are also discussed.

Details

Aircraft Engineering and Aerospace Technology, vol. 72 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

Expert briefing
Publication date: 13 August 2015

The outlook for the F-35.

Article
Publication date: 19 June 2019

Daniel Klatt, Michael Proff and Robert Hruschka

The present work aims to investigate the capabilities of accurately predicting the six-degrees-of-freedom (6DoF) trajectory and the flight behavior of a flare-stabilized…

Abstract

Purpose

The present work aims to investigate the capabilities of accurately predicting the six-degrees-of-freedom (6DoF) trajectory and the flight behavior of a flare-stabilized projectile using computational fluid dynamics (CFD) and rigid body dynamics (RBD) methods.

Design/methodology/approach

Two different approaches are compared for calculating the trajectory. First, the complete matrix of static and dynamic aerodynamic coefficients for the projectile is determined using static and dynamic CFD methods. This discrete database and the data extracted from free-flight experiments are used to simulate flight trajectories with an in-house developed 6DoF solver. Second, the trajectories are simulated solving the 6DoF motion equations directly coupled with time resolved CFD methods.

Findings

Virtual fly-out simulations using RBD/CFD coupled simulation methods well reproduce the motion behavior shown by the experimental free-flight data. However, using the discrete database of aerodynamic coefficients derived from CFD simulations shows a slightly different flight behavior.

Originality/value

A discrepancy between CFD 6DoF/RBD simulations and results obtained by the MATLAB 6DoF-solver based on discrete CFD data matrices is shown. It is assumed that not all dynamic effects on the aerodynamics of the projectile are captured by the determination of the force and moment coefficients with CFD simulations based on the classical aerodynamic coefficient decomposition.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 11 December 2019

Linus Meier and Michael Eglin

Metalworking fluids can significantly increase the tool life in titanium cutting, however, full-scale cutting tests to determine the performance of metalworking fluid are…

160

Abstract

Purpose

Metalworking fluids can significantly increase the tool life in titanium cutting, however, full-scale cutting tests to determine the performance of metalworking fluid are expensive. The aim of this study is therefore to introduce a reliable and inexpensive alternative testing method.

Design/methodology/approach

A newly developed in-process tribometer allows emulating the sliding conditions of the chip formed in cutting as closely as possible. It uses a cutting action in front of a pin to eliminate the influence of the oxidation layer. To observe the wear pattern on the pin, adhering workpiece material is removed by selective etching. A high temperature oxidation test is used to study the wear mechanism.

Findings

The wear pattern on the pin correlates well with the wear pattern observed on cutting tools when using the same metalworking fluid while being much more cost-effective than a tool life test. The high temperature oxidation test reveals that cobalt leaching is causing notch wear.

Research limitations/implications

The correlation between pin and tool wear is verified for the case of roughing turning of titanium with cemented carbide tools and two metalworking fluids.

Practical implications

The method is applicable in an industrial context, potentially replacing the currently used tribological analyzes.

Social implications

Submitted in connection with the special issue “young tribologists – insights into the work of the new generation”.

Originality/value

Methods tailored to model the tool wear in titanium cutting are rare. For the first time, an in-process tribometer, which is especially suited for the analysis of titanium cutting, is used to assess the wear behavior. The design of the high temperature oxidation test is new.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0311

Details

Industrial Lubrication and Tribology, vol. 72 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 April 1951

Cold weather operation of aircraft presented important problems during World War II, and these have continued to grow until today, all specifications for United Stales Air…

Abstract

Cold weather operation of aircraft presented important problems during World War II, and these have continued to grow until today, all specifications for United Stales Air Force equipment contains the requirement for satisfactory operation at —65°F. One of the major problems has been cold starting. The USAF have established testing bases for overcoming these problems at Ladd, Alaska, Eglin, Florida, the observatory at Ml. Washington, and the Power Plant Laboratory at Wright‐Patterson AF Base, Dayton, Ohio. In a paper recently presented before the Society of Automotive Engineers at Detroit, Saul Barron of the Air Material Command Power Plant Laboratory, dealt with these problems and described the steps being taken by the USAF to solve them. We give a shortened version of his paper.

Details

Industrial Lubrication and Tribology, vol. 3 no. 4
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 1 February 1992

J. Daniel Stewart and Daniel Rameli

Outlines the implementation of Total Quality Management at the US Air Force Development Test Centre at Elgin Air Force Base in Florida. Discusses the steps in the…

Abstract

Outlines the implementation of Total Quality Management at the US Air Force Development Test Centre at Elgin Air Force Base in Florida. Discusses the steps in the implementation process, focusing on management awareness, strategic planning, management implementation and employee training. Details the procedure of cascading the concepts, philosophy, methods and tools of quality management from the top of the organization downwards and relates the timescale necessary to do this.

Details

Managing Service Quality: An International Journal, vol. 2 no. 2
Type: Research Article
ISSN: 0960-4529

Keywords

Article
Publication date: 1 June 1994

From all indications from both company pilots and others who have flown and examined the MD Explorer, the new commercial helicopter from McDonnell Douglas, the potential…

Abstract

From all indications from both company pilots and others who have flown and examined the MD Explorer, the new commercial helicopter from McDonnell Douglas, the potential operators, known within McDonnell Douglas as the “Blue Team”, who contributed to its design and development, are getting exactly what they asked for.

Details

Aircraft Engineering and Aerospace Technology, vol. 66 no. 6
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 22 June 2010

Jian Fang, Yubin Sun, Yanqiu Xia and Weimin Liu

The purpose of this paper is to understand the effect of base media on the tribological performance and tribochemistry of bismuth thiophosphate additive.

Abstract

Purpose

The purpose of this paper is to understand the effect of base media on the tribological performance and tribochemistry of bismuth thiophosphate additive.

Design/methodology/approach

The oil‐water double soluble additive bismuth dithiophosphate was prepared and identified. The contributions of the two base media on the additive tribological behavior and the tribofilm components were comparatively studied.

Findings

The extreme pressure (EP) and friction‐reducing properties are remarkably improved with water substituted for paraffin as the base medium. The EP performance of the lubricating media containing this additive mainly results from the tribochemical reaction film on the rubbing surface, not from the viscosity of the base media. In water or paraffin medium, the adsorption process of this additive from the lubricant bulk onto the rubbing surface and the components and the properties of the tribochemical reaction films formed are different, which have important effect on the tribological performance.

Research limitations/implications

The paper mainly focuses on how the water medium with polarity and the liquid paraffin base medium with non‐polarity affect on the tribological performance of the bismuth thiophosphate additive.

Practical implications

The research has found a water‐oil double soluble lubrication additive with outstanding EP and friction‐reducing performance.

Originality/value

The designed experiment provides a new approach to further learn the action mechanism of thiophosphate additive.

Details

Industrial Lubrication and Tribology, vol. 62 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 March 1994

Eric Sandelands

This special “Anbar Abstracts” issue of Employee Relations is split into seven sections covering abstracts under the following headings: Design of Work; Performance…

Abstract

This special “Anbar Abstracts” issue of Employee Relations is split into seven sections covering abstracts under the following headings: Design of Work; Performance, Productivity and Motivation; Patterns of Work; Pay, Incentives and Pensions; Career/Manpower Planning ; Industrial Relations and Participation; Health and Safety.

Details

Employee Relations, vol. 16 no. 3
Type: Research Article
ISSN: 0142-5455

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