Pub Date : 2019-12-31DOI: 10.1515/9781400851324-005
Frank Ledwidge
Once powered aircraft had taken to the air in the early 20th century, it did not take long for their potential as a military instrument to be realized. The First World War demonstrated that aeroplanes would indeed be war machines, and very formidable ones. ‘Beginnings: the First World War 1914–1918’ explains that whilst it was never a decisive arm on any WW1 front, all the elements of aircraft’s future deployment were present with the exception of its mobility potential. By the end of the war, the combatant nations had thousands of aircraft in their inventories with their attendant administrative and logistical structures. The world’s first independent air arm, the Royal Air Force, had been formed.
{"title":"2 Beginnings","authors":"Frank Ledwidge","doi":"10.1515/9781400851324-005","DOIUrl":"https://doi.org/10.1515/9781400851324-005","url":null,"abstract":"Once powered aircraft had taken to the air in the early 20th century, it did not take long for their potential as a military instrument to be realized. The First World War demonstrated that aeroplanes would indeed be war machines, and very formidable ones. ‘Beginnings: the First World War 1914–1918’ explains that whilst it was never a decisive arm on any WW1 front, all the elements of aircraft’s future deployment were present with the exception of its mobility potential. By the end of the war, the combatant nations had thousands of aircraft in their inventories with their attendant administrative and logistical structures. The world’s first independent air arm, the Royal Air Force, had been formed.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"40 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79808034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study comparatively analyzes the calculation performances of different large-eddy simulation (LES) combustion models in a diffused flame simulation to investigate the performances of different LES-turbulent combustion models. The flamelet/progress variable (FPV), partially stirred reactor (PaSR), and transport joint possibility density function (PDF) combustion model are adopted to perform a numerical simulation analysis for Flame D in the Sandia Lab. The comparison between the calculation results and the test data shows that the three models can properly simulate the diffused flame. The transport PDF model based on the Eulerian stochastic field method can realize better results, especially the forecast for the intermediate radicals (OH) and the pollutant emissions (NO). However, the calculation volume is huge. The calculation speed and precision of PaSR are acceptable. The FPV method can save much CPU time, and has great value in engineering applications. (Less)
{"title":"Comparison study on LES combustion models in diffusion flame","authors":"Xiao Liu, C. Gong, Zhiming Li, Hongtao Zheng","doi":"10.11990/JHEU.201705045","DOIUrl":"https://doi.org/10.11990/JHEU.201705045","url":null,"abstract":"This study comparatively analyzes the calculation performances of different large-eddy simulation (LES) combustion models in a diffused flame simulation to investigate the performances of different LES-turbulent combustion models. The flamelet/progress variable (FPV), partially stirred reactor (PaSR), and transport joint possibility density function (PDF) combustion model are adopted to perform a numerical simulation analysis for Flame D in the Sandia Lab. The comparison between the calculation results and the test data shows that the three models can properly simulate the diffused flame. The transport PDF model based on the Eulerian stochastic field method can realize better results, especially the forecast for the intermediate radicals (OH) and the pollutant emissions (NO). However, the calculation volume is huge. The calculation speed and precision of PaSR are acceptable. The FPV method can save much CPU time, and has great value in engineering applications. (Less)","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"39 1","pages":"496-502"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66001916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.3969/J.ISSN.1006-7043.201404019
Y. Wan, Jifeng Zhang, Zhenqing Wang, Li Min Zhou
In order to investigate the failure mechanism of glass-fiber reinforced aluminum( GLARE) laminates under impact loading,the anti-low speed impact performance by a dropweight test on GLARE was presented,and the damage response of GLARE laminates in the test was given. The study first analyses the curves of time-contact force,time-deflection,time-absorbed energy,deflection-contact force,and the damage to two aluminum layers of the test specimen. Next,a numerical methodology in ABAQUS is employed to simulate the response in low-velocity impact of GLARE laminates and establish the finite element model. After comparing the time-contact force,timedeflection,time-absorbed energy,and the damage to aluminum layers under different circumstances of impact energy between experimental and simulation results,the reliability of the finite element model method was validated. After comparing the damages to composites and aluminum under different impact energy,no big difference in the damage to the composite layer was found. However,more damage in the aluminum layer when the impact energy is higher was found,proving that the aluminum layers play an important role in the entire anti-impact performance of materials.
{"title":"Low-velocity impact damage on glass fibre reinforced aluminium laminates: experiments and finite element analysis","authors":"Y. Wan, Jifeng Zhang, Zhenqing Wang, Li Min Zhou","doi":"10.3969/J.ISSN.1006-7043.201404019","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.201404019","url":null,"abstract":"In order to investigate the failure mechanism of glass-fiber reinforced aluminum( GLARE) laminates under impact loading,the anti-low speed impact performance by a dropweight test on GLARE was presented,and the damage response of GLARE laminates in the test was given. The study first analyses the curves of time-contact force,time-deflection,time-absorbed energy,deflection-contact force,and the damage to two aluminum layers of the test specimen. Next,a numerical methodology in ABAQUS is employed to simulate the response in low-velocity impact of GLARE laminates and establish the finite element model. After comparing the time-contact force,timedeflection,time-absorbed energy,and the damage to aluminum layers under different circumstances of impact energy between experimental and simulation results,the reliability of the finite element model method was validated. After comparing the damages to composites and aluminum under different impact energy,no big difference in the damage to the composite layer was found. However,more damage in the aluminum layer when the impact energy is higher was found,proving that the aluminum layers play an important role in the entire anti-impact performance of materials.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"36 1","pages":"769-773"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-01-01DOI: 10.3969/J.ISSN.1006-7043.201405052
Zhiguo Yuan, L. Fan, Y. Bai, Chao Chen, Xiuzhen Ma
An electronic unit pump (EUP) is a fuel injection system which can satisfy the requirement of diesel engine's power performance and emission characteristics. In order to investigate the fluctuation in small cycle fuel injection quantity of the diesel engine at low loads, a numerical model of the EUP system was built in the AMESim environment and its accuracy was verified by experiment. The quantitative relationship between the fluctuation in minorcycle fuel injection quantity and every key parameter was studied in different cam speeds. The quantitative percentage index of the different parameters is obtained. At the same time, combining the central composite design experimental method, and taking into account the interaction of different characteristic factors, the correlation coefficients of different factors and minor cycle fuel injection quantity are revealed after the correlation analysis.
{"title":"Key influence factors of small cycle fuel injection quantity for an electronic unit pump system of diesel engines","authors":"Zhiguo Yuan, L. Fan, Y. Bai, Chao Chen, Xiuzhen Ma","doi":"10.3969/J.ISSN.1006-7043.201405052","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.201405052","url":null,"abstract":"An electronic unit pump (EUP) is a fuel injection system which can satisfy the requirement of diesel engine's power performance and emission characteristics. In order to investigate the fluctuation in small cycle fuel injection quantity of the diesel engine at low loads, a numerical model of the EUP system was built in the AMESim environment and its accuracy was verified by experiment. The quantitative relationship between the fluctuation in minorcycle fuel injection quantity and every key parameter was studied in different cam speeds. The quantitative percentage index of the different parameters is obtained. At the same time, combining the central composite design experimental method, and taking into account the interaction of different characteristic factors, the correlation coefficients of different factors and minor cycle fuel injection quantity are revealed after the correlation analysis.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70176303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With consideration to the problems of conventional code shift keying( CSK),specifically with the low data communication rate and the existing strong interference between the channels of conventional orthogonal CSK which adopts the m sequence,the quadrature CSK spread spectrum underwater acoustic( UWA) communication technology utilizing the small Kasami sequence is proposed. The purpose is to reduce the interference between channels effectively,and enhance performance through optimization and combination in the sequence and communication scheme. This paper describes the factors influencing system performance and how the factors were deduced and analyzed by using specific formulas and then these factors were compared to the sequence correlation properties and the simulation performance of the communication system composed of this sequence. Finally,the experimentation results showed that the proposed scheme is superior to the conventional methods in performance.
{"title":"Orthogonal code shift keying spread spectrum underwater acoustic communications employing the small Kasami sequence","authors":"Yu Yan","doi":"10.7498/aps.62.064302","DOIUrl":"https://doi.org/10.7498/aps.62.064302","url":null,"abstract":"With consideration to the problems of conventional code shift keying( CSK),specifically with the low data communication rate and the existing strong interference between the channels of conventional orthogonal CSK which adopts the m sequence,the quadrature CSK spread spectrum underwater acoustic( UWA) communication technology utilizing the small Kasami sequence is proposed. The purpose is to reduce the interference between channels effectively,and enhance performance through optimization and combination in the sequence and communication scheme. This paper describes the factors influencing system performance and how the factors were deduced and analyzed by using specific formulas and then these factors were compared to the sequence correlation properties and the simulation performance of the communication system composed of this sequence. Finally,the experimentation results showed that the proposed scheme is superior to the conventional methods in performance.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71343532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.3969/J.ISSN.1006-7043.201311041
Liubin Zhou, Tiejun Yang, M. Brennan, Zhi-gang Liu
For the purpose of solving the problems of vibration transmission and sound radiations in ships,synchrophasing control technology was presented. The phases of multiple rotating or reciprocating machines installed on a floating raft were adjusted by synchrophasing control to minimize vibration transmission from the floating raft to a hull structure,and then as a result the sound radiation from the hull structure was reduced reasonably. Relative phases between each of the two vibrating machines were optimized in order to minimize the sum of the squared acceleration responses of the hull structure by using genetic algorithm. Synchrophasing control for the floating raft vibration isolation system installed on a flexible hull-like structure was investigated theoretically and experimentally. The results show that by comparing the optimal phases and the least optimal phases,the maximum reduction of the sum of squared acceleration responses measured by 22 error sensors on the hull structure and the maximum reduction of the mean squared sound pressures measured by 10 microphones around it are up to 13. 2 dB and 20. 4 dB by synchrophasing control,respectively. Synchrophasing control is a simple and efficient method for controlling the vibration transmission and sound radiations of the hull structure.
{"title":"On synchrophasing control of vibration and sound radiation for a floating raft vibration isolation system","authors":"Liubin Zhou, Tiejun Yang, M. Brennan, Zhi-gang Liu","doi":"10.3969/J.ISSN.1006-7043.201311041","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.201311041","url":null,"abstract":"For the purpose of solving the problems of vibration transmission and sound radiations in ships,synchrophasing control technology was presented. The phases of multiple rotating or reciprocating machines installed on a floating raft were adjusted by synchrophasing control to minimize vibration transmission from the floating raft to a hull structure,and then as a result the sound radiation from the hull structure was reduced reasonably. Relative phases between each of the two vibrating machines were optimized in order to minimize the sum of the squared acceleration responses of the hull structure by using genetic algorithm. Synchrophasing control for the floating raft vibration isolation system installed on a flexible hull-like structure was investigated theoretically and experimentally. The results show that by comparing the optimal phases and the least optimal phases,the maximum reduction of the sum of squared acceleration responses measured by 22 error sensors on the hull structure and the maximum reduction of the mean squared sound pressures measured by 10 microphones around it are up to 13. 2 dB and 20. 4 dB by synchrophasing control,respectively. Synchrophasing control is a simple and efficient method for controlling the vibration transmission and sound radiations of the hull structure.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":"1 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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