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Author

Sriram Rengarajan

Bio: Sriram Rengarajan is an academic researcher from University of Glasgow. The author has contributed to research in topics: Payload & Conceptual design. The author has an hindex of 4, co-authored 5 publications receiving 24 citations.

Papers
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Proceedings ArticleDOI
02 Mar 2017
TL;DR: In this article, the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads is presented, which uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits.
Abstract: This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs.

7 citations

Journal ArticleDOI
01 May 2019
TL;DR: The results show that the proper filter method and the background image subtraction can effectively eliminate the image noises in frequency domain, which makes it easier to analyze the flow structure.
Abstract: Schlieren and shadowgraph photography has been widely used to offer insight into the flow field in aerospace engineering due to their ease of application. The high-speed schlieren and shadowgraph techniques are typically applied to investigation of unsteady shock wave structure including shock reflection patterns and shock wave/boundary layer interactions, etc. Generally, qualitative analysis is performed based on the schlieren and shadowgraph image sequences. To process and analyze the large data set of the high-speed schlieren and shadowgraph images quantitatively, especially for the shock wave detection and tracking, a software was developed based on MATLAB GUI and its image processing toolbox. In this study, the image processing techniques exploited in the software, such as background subtraction, filter, threshold, edge detection, and shock tracking are presented. A case study on the phenomena of shock wave reflection from a solid surface was conducted. The results show that the proper filter method and the background image subtraction can effectively eliminate the image noises in frequency domain, which makes it easier to analyze the flow structure. Moreover, the instantaneous locations of shock waves are detected accurately, and the shock wave propagation speed calculated using the developed software are consistent with those of previous studies.

6 citations

26 Oct 2016
TL;DR: The Future UK Small Payload Launcher (FSPLUK) as mentioned in this paper is an air launched integrated re-usable first stage vehicle, configured with a flexible internal payload bay from which one or more upper stages are deployed.
Abstract: Miniaturisation of satellite componentry, increasingly capable small sensors and substantial increases in processing capacity and transmission bandwidth are driving rapid growth in small payload development and consequential launch demand. The advent of horizontal take-off spaceports opens the door for a new generation of small payload launch systems that will fulfil this demand. However, the key to a launch system's success is its ability to provide a return on the substantial costs of development while delivering pricing levels commensurate with the needs of launch customers. Therefore, commercially led design approaches are needed to refine and optimise the design of the new small payload launch systems required. This approach was embodied in an ongoing UKSA funded NSTP2 project titled Future UK Small Payload Launcher (FSPLUK). The approach is first founded upon a bespoke and specific market assessment. This characterises, segments and quantifies the commercial opportunity and establishes principal desired system performance requirements. An assessment of available technologies at differing TRLs permits initial vehicle configuration options to be developed and technically assessed. Technically viable options are then assessed in terms of commercial viability with the best advanced into more detailed technical assessment and system optimisation. The resultant vehicles are again tested for commercial viability and, if successful, emerge as recommended development avenues. Using these methods, it has been possible to iterate design concepts from apparently simple yet economically sub-optimised stacked launcher systems through several design iterations to a resultant highly flexible and economically efficient conceptual design. The key finding relates to the inter-relationship between payload flexibility, in permitting maximised flight rates from a reasonably complex but highly reusable first stage design, and low disposable upper stage unit cost. This has driven the resultant system to feature an air launched integrated re-usable first stage vehicle, configured with a flexible internal payload bay from which one or more upper stages are deployed. This configuration maximises commercial utility and reusability. The resultant high flight rate allows development costs to be efficiently amortised with minimised direct launch costs. The configuration therefore meets low cost per kg price targets while delivering a positive return on development expenditure over life. It also provides a flight proven vehicle platform with available internal real-estate for application as a hypersonic air test platform for new propulsion systems, such as SABRE. The commercially led approach has created the foundation for viable and economically justifiable development.

5 citations

26 Oct 2016
TL;DR: In this paper, the authors describe a preferable vehicle classification alongside a brief description of key technologies available on the shelf or under development to address the demand of the small payload market, followed by a discussion on the investigation of the current market and the future forecast; regarding the delivery of small payloads into orbit.
Abstract: This paper describes a preferable vehicle classification alongside a brief description of key technologies available on the shelf or under development to address the demand of the small payload market. This is followed by a discussion on the investigation of the current market and the future forecast; regarding the delivery of small payloads into orbit.

5 citations

Journal ArticleDOI
TL;DR: The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies and on the commercial potential of the technical design.

5 citations


Cited by
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01 Jan 2016
TL;DR: The international space station is universally compatible with any devices to read, allowing you to get the most less latency time to download any of the authors' books like this one.
Abstract: Thank you very much for reading international space station. Maybe you have knowledge that, people have search numerous times for their chosen novels like this international space station, but end up in malicious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some malicious virus inside their desktop computer. international space station is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the international space station is universally compatible with any devices to read.

27 citations

Journal ArticleDOI
TL;DR: In this article, a novel approach to the solution of multiphase multi-objective optimal control problems is presented, which is based on the transcription of the optimal control probabilistic model.
Abstract: This paper presents a novel approach to the solution of multiphase multi-objective optimal control problems. The proposed solution strategy is based on the transcription of the optimal control prob...

18 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed and demonstrated a novel shock tube driven by commercially available detonation transmission tubing in a safe, repeatable, and controllable manner for laboratory scale experiments.

13 citations

Proceedings ArticleDOI
02 Mar 2017
TL;DR: In this article, the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads is presented, which uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits.
Abstract: This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs.

7 citations

Journal ArticleDOI
17 Dec 2020
TL;DR: It was shown, that the machine learning approach gives better results in shock wave detection accuracy, especially for low-quality images with a strong noise level.
Abstract: Schlieren, shadowgraph and other types of refraction-based techniques have been often used to study gas flow structures. They can capture strong density gradients, such as shock waves. Shock wave detection is a very important task in analyzing unsteady gas flows. High-speed imaging systems, including high-speed cameras, are widely used to record large arrays of shadowgraph images. To process large datasets of the high-speed shadowgraph images and automatically detect shock waves, convective plumes and other gas flow structures, two computer software systems based on the edge detection and machine learning with convolutional neural networks (CNN) were developed. The edge-detection software utilizes image filtering, noise removing, background image subtraction in the frequency domain and edge detection based on the Canny algorithm. The machine learning software is based on CNN. We developed two neural networks working together. The first one classifies the image dataset and finds images with shock waves. The other CNN solves the regression task and defines shock wave position (single number) based on image pixels tensor (3-D array of numbers) for each image. The supervised learning code based on example input-output pairs was developed to train models. It was shown, that the machine learning approach gives better results in shock wave detection accuracy, especially for low-quality images with a strong noise level. Software system for automated shadowgraph images processing and x-t curves of the shock wave and convective plume movement plotting was developed.

6 citations