Rolls-Royce Motor Cars

About: Rolls-Royce Motor Cars is a based out in . It is known for research contribution in the topics: Turbine & Gas compressor. The organization has 3845 authors who have published 4934 publications receiving 58973 citations. The organization is also known as: Rolls-Royce Motor Cars Limited.

Experimental Investigation Into Unsteady Effects on Film Cooling

Abstract: The benefits of different film cooling geometries are typically assessed in terms of their time-averaged performance. It is known that the mixing between the coolant film and the main turbine passage flow is an unsteady process. The current study investigates the forms of unsteadiness that occur in engine-representative film cooling flows and how this unsteadiness affects the mixing with the mainstream flow. Cylindrical and fan-shaped cooling holes across a range of hole blowing ratios have been studied experimentally using particle image velocimetry and high speed photography. Coherent unsteadiness is found in the shear layer between the jet and the mainstream for both cylindrical and fan-shaped cooling holes. Its occurrence and sense of rotation is found to be controlled by the velocity difference between the mainstream flow and the jet, which is largely determined by the blowing ratio.

Cyber-Resilient Cooperative Control of Bidirectional Interlinking Converters in Networked AC/DC Microgrids

Abstract: Bidirectional interlinking converters (BICs) are building blocks of the networked ac/dc microgrids (ac/dc NMGs). Such BICs are controlled using the communication assisted cooperative control thus forming tightly coupled cyber-physical systems (CPSs). One of lethal problems in such CPS is its vulnerability to cyber-attacks. In this article, a cyber-resilient cooperative control for BICs in ac/dc NMGs is proposed to enhance the system resilience under false signal injection attacks. The proposed control can maintain the frequency/voltage regulation and real/reactive power sharing among multiple BICs under both single and multiple node attacks. The suitability of the proposed method is supported by the stability analysis using Lyapunov methods. Efficacy of the proposed method is demonstrated by the controller hardware-in-the-loop (CHIL) experiment. An ac/dc NMG with four BICs is developed in the OPAL-RT-based real-time simulator. The cyber-resilient controllers are implemented on four commercial programmable logic controllers by B&R automation. The CHIL-based experimental results support the effectiveness of the proposed controller under various attack scenarios.

EARS (Easy Approach to Requirements Syntax)

Abstract: The development of complex systems frequently involves extensive work to elicit, document and review stakeholder requirements. Stakeholder requirements are usually written in unconstrained natural language, which is inherently imprecise. During system development, problems in stakeholder requirements inevitably propagate to lower levels. This creates unnecessary volatility and risk, which impact programme schedule and cost. Some experts advocate the use of other notations to increase precision and minimise problems such as ambiguity. However, use of non-textual notations requires translation of the source requirements, which can introduce further errors. There is also a training overhead associated with the introduction of new notations. A small set of structural rules was developed to address eight common requirement problems including ambiguity, complexity and vagueness. The ruleset allows all natural language requirements to be expressed in one of five simple templates. The ruleset was applied whilst extracting aero engine control system requirements from an airworthiness regulation document. The results of this case study show qualitative and quantitative improvements compared with a conventional textual requirements specification.