Iresha Atthanayake | The Open University (original) (raw)
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Papers by Iresha Atthanayake
Engineer: Journal of the Institution of Engineers, Sri Lanka, 2021
Deaf and Mute people cannot communicate efficiently to express their feelings to ordinary people.... more Deaf and Mute people cannot communicate efficiently to express their feelings to ordinary people. The common method these people use for communication is the sign language. But these sign languages are not very familiar to ordinary people. Therefore, effective communication between deaf and mute people and ordinary people is seriously affected. This paper presents the development of an Android mobile application to translate sign language into speech-language for ordinary people, and speech into text for deaf and mute people using Convolution Neural Network (CNN). The study focuses on vision-based Sign Language Recognition (SLR) and Automatic Speech Recognition (ASR) mobile application. The main challenging tasks were audio classification and image classification. Therefore, CNN was used to train audio clips and images. Mel-frequency Cepstral Coefficient (MFCC) approach was used for ASR. The mobile application was developed by Python programming and Android Studio. After developing the application, testing was done for letters A and C, and these letters were identified with 95% accuracy.
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19 % of world electricity. Many hydro power plants are operated with Pelton turbines, which is an impulse turbine. The main reasons for using impulse turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Scientific investigation and design of turbines saw rapid advancement during last century. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade friction on the performance of turbine. The main focus in this paper is to analyze the performance of Pelton turbine particularly with respect to their blade friction.
Turbulent Cascades II, 2019
We present results of a particle image velocimetry (PIV) study conducted on forced plumes in a ro... more We present results of a particle image velocimetry (PIV) study conducted on forced plumes in a rotating system. The measurements were carried out for nine different background rotations and it was found that the plume precesses anticyclonically around the axis of background rotation. The data analysis has revealed that the precession rate increases linearly with the rate of background rotation. Open image in new window
Experimental results from comprehensive PIV measurements investigating the dynamics of turbulent ... more Experimental results from comprehensive PIV measurements investigating the dynamics of turbulent jets in a rotating fluid are presented. It is observed that background system rotation induces a time-periodic formation-breakdown cycle of the jets. The flow dynamics associated with this process are studied in detail. It is found that the frequency of the cycle increases linearly with the background rotation rate. The data show that the onset of the breakdown phase and of the reformation phase of the cycle can be characterized in terms of a local Rossby number employing an internal velocity and length scale of the jet. The critical values for this local Rossby number, for onset of breakdown and reformation, scale linearly with a global Rossby number based on the flow conditions at the source. The analysis of the experimental data in terms of relevant stability criteria suggests that the formation-breakdown cycle is due to centrifugal instability and that the temporally fluctuating axia...
IEEE Transactions on Molecular, Biological and Multi-Scale Communications, 2020
ICC 2020 - 2020 IEEE International Conference on Communications (ICC), 2020
Proceedings of the 5th ACM International Conference on Nanoscale Computing and Communication, 2018
Please refer to published version for the most recent bibliographic citation information. If a pu... more Please refer to published version for the most recent bibliographic citation information. If a published version is known of, the repository item page linked to above, will contain details on accessing it.
Journal of Fluid Mechanics, 2019
Results of comprehensive particle image velocimetry measurements investigating the dynamics of tu... more Results of comprehensive particle image velocimetry measurements investigating the dynamics of turbulent jets in a rotating fluid are presented. It is observed that background system rotation induces a time-periodic formation–breakdown cycle of the jets. The flow dynamics associated with this process is studied in detail. It is found that the frequency of the cycle increases linearly with the background rotation rate. The data show that the onset of the breakdown phase and of the reformation phase of the cycle can be characterized in terms of a local Rossby number employing an internal velocity and a length scale of the jet. The critical values for this local Rossby number, for onset of breakdown and reformation, scale linearly with a global Rossby number based on the flow conditions at the source. The analysis of the experimental data suggests centrifugal instability as the potential origin of the formation–breakdown cycle.
International Journal of Fluid Machinery and Systems, 2011
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity. Many hydro power plants are operated with Pelton turbines, which is an impulse turbine. The main reasons for using impulse turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Scientific investigation and design of turbines saw rapid advancement during last century. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade friction on the performance of turbine. The main focus in this paper is to analyze the performance of Pelton turbine particularly with respect to their blade friction.
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity and 44% (as at 2012) of Sri Lanka's electricity also comes from hydropower. Micro Hydro is a term used for hydroelectric power installations that typically produce up to 20 kW of power in Sri Lankan context. Many Micro-hydro power plants are operated with Pelton turbines. The main reasons for using Pelton turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Since most of the micro hydro Pelton turbines are now manufactured locally, it was revealed that much attention is not paid to the surface finish of the turbine buckets. On the other hand due to sand erosion of turbine parts bucket surface are getting rough day by day. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade/bucket friction on the performance of Pelton turbine. The main objective of this research is to analyze the performance of Micro hydro Pelton turbine particularly with respect to their blade friction. vi Finally I would like to thank my family members who are always behind me and encouraging me for better future. There the strength of my life. I would like to thank particularly to my husband for releasing me from all household responsibilities for this period. vii
Engineer: Journal of the Institution of Engineers, Sri Lanka, 2021
Deaf and Mute people cannot communicate efficiently to express their feelings to ordinary people.... more Deaf and Mute people cannot communicate efficiently to express their feelings to ordinary people. The common method these people use for communication is the sign language. But these sign languages are not very familiar to ordinary people. Therefore, effective communication between deaf and mute people and ordinary people is seriously affected. This paper presents the development of an Android mobile application to translate sign language into speech-language for ordinary people, and speech into text for deaf and mute people using Convolution Neural Network (CNN). The study focuses on vision-based Sign Language Recognition (SLR) and Automatic Speech Recognition (ASR) mobile application. The main challenging tasks were audio classification and image classification. Therefore, CNN was used to train audio clips and images. Mel-frequency Cepstral Coefficient (MFCC) approach was used for ASR. The mobile application was developed by Python programming and Android Studio. After developing the application, testing was done for letters A and C, and these letters were identified with 95% accuracy.
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19 % of world electricity. Many hydro power plants are operated with Pelton turbines, which is an impulse turbine. The main reasons for using impulse turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Scientific investigation and design of turbines saw rapid advancement during last century. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade friction on the performance of turbine. The main focus in this paper is to analyze the performance of Pelton turbine particularly with respect to their blade friction.
Turbulent Cascades II, 2019
We present results of a particle image velocimetry (PIV) study conducted on forced plumes in a ro... more We present results of a particle image velocimetry (PIV) study conducted on forced plumes in a rotating system. The measurements were carried out for nine different background rotations and it was found that the plume precesses anticyclonically around the axis of background rotation. The data analysis has revealed that the precession rate increases linearly with the rate of background rotation. Open image in new window
Experimental results from comprehensive PIV measurements investigating the dynamics of turbulent ... more Experimental results from comprehensive PIV measurements investigating the dynamics of turbulent jets in a rotating fluid are presented. It is observed that background system rotation induces a time-periodic formation-breakdown cycle of the jets. The flow dynamics associated with this process are studied in detail. It is found that the frequency of the cycle increases linearly with the background rotation rate. The data show that the onset of the breakdown phase and of the reformation phase of the cycle can be characterized in terms of a local Rossby number employing an internal velocity and length scale of the jet. The critical values for this local Rossby number, for onset of breakdown and reformation, scale linearly with a global Rossby number based on the flow conditions at the source. The analysis of the experimental data in terms of relevant stability criteria suggests that the formation-breakdown cycle is due to centrifugal instability and that the temporally fluctuating axia...
IEEE Transactions on Molecular, Biological and Multi-Scale Communications, 2020
ICC 2020 - 2020 IEEE International Conference on Communications (ICC), 2020
Proceedings of the 5th ACM International Conference on Nanoscale Computing and Communication, 2018
Please refer to published version for the most recent bibliographic citation information. If a pu... more Please refer to published version for the most recent bibliographic citation information. If a published version is known of, the repository item page linked to above, will contain details on accessing it.
Journal of Fluid Mechanics, 2019
Results of comprehensive particle image velocimetry measurements investigating the dynamics of tu... more Results of comprehensive particle image velocimetry measurements investigating the dynamics of turbulent jets in a rotating fluid are presented. It is observed that background system rotation induces a time-periodic formation–breakdown cycle of the jets. The flow dynamics associated with this process is studied in detail. It is found that the frequency of the cycle increases linearly with the background rotation rate. The data show that the onset of the breakdown phase and of the reformation phase of the cycle can be characterized in terms of a local Rossby number employing an internal velocity and a length scale of the jet. The critical values for this local Rossby number, for onset of breakdown and reformation, scale linearly with a global Rossby number based on the flow conditions at the source. The analysis of the experimental data suggests centrifugal instability as the potential origin of the formation–breakdown cycle.
International Journal of Fluid Machinery and Systems, 2011
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity. Many hydro power plants are operated with Pelton turbines, which is an impulse turbine. The main reasons for using impulse turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Scientific investigation and design of turbines saw rapid advancement during last century. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade friction on the performance of turbine. The main focus in this paper is to analyze the performance of Pelton turbine particularly with respect to their blade friction.
Water turbines have been used in electricity generation for well over a century. Hydroelectricity... more Water turbines have been used in electricity generation for well over a century. Hydroelectricity now supplies 19% of world electricity and 44% (as at 2012) of Sri Lanka's electricity also comes from hydropower. Micro Hydro is a term used for hydroelectric power installations that typically produce up to 20 kW of power in Sri Lankan context. Many Micro-hydro power plants are operated with Pelton turbines. The main reasons for using Pelton turbines are that they are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing the number of nozzles or by using adjustable nozzles. Since most of the micro hydro Pelton turbines are now manufactured locally, it was revealed that much attention is not paid to the surface finish of the turbine buckets. On the other hand due to sand erosion of turbine parts bucket surface are getting rough day by day. Most of the research that had been done on turbines were focused on improving the performance with particular reference to turbine components such as shaft seals, speed increasers and bearings. There is not much information available on effects of blade/bucket friction on the performance of Pelton turbine. The main objective of this research is to analyze the performance of Micro hydro Pelton turbine particularly with respect to their blade friction. vi Finally I would like to thank my family members who are always behind me and encouraging me for better future. There the strength of my life. I would like to thank particularly to my husband for releasing me from all household responsibilities for this period. vii