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Power and Trim Estimation for Helicopter Sizing and Performance Analysis
Laxman, Vaitla,Lim, Jae-Hoon,Shin, Sang-Joon,Ko, Kwang-Ho,Jung, Sung-Nam The Korean Society for Aeronautical and Space Scie 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2
The preliminary design stage of helicopters consists of various operations and in each operation design several detailed analysis tasks are needed. The analysis tasks include performance and the required power estimation. In helicopter design, those are usually carried out by adopting the momentum theory. In this paper, an explicit form of computational analysis based on the blade element theory and uniform/non-uniform inflow model is developed. The other motivation of the present development is to obtain trim and required power estimation for various helicopter configurations. Sectional and hub loads, power, trim, and flapping equations are derived by using a symbolic tool. Iterative computations are carried out till convergence is achieved in the blade response, inflow, and trim. The predictions regarding the trim and power estimation turn out to be correlated well with the experimental results. The effect of inflow is further investigated. It is found that the present prediction for the lateral cyclic pitch angle is improved with the non-uniform inflow model as compared to that by the uniform inflow model. The presently improved trim and power estimation will be useful for future helicopter sizing and performance analysis.
India`s Defense Acquisition System: Need for Further Reforms
( Laxman Kumar Behera ) 한국국방연구원 2012 The Korean Journal of Defense Analysis Vol.24 No.1
India`s defense acquisition system has evolved over the years and now consists of hierarchical and institutional structures and detailed procedures. The evolved system has created an atmosphere for undertaking acquisition in a more methodical, process-oriented and objective manner. The success of the evolved system is evident from its ability to execute orders worth billions of dollars every year. However, despite all the success of the evolved system there are certain weak areas that demander forms to make the system more accountable and deliver within a prescribed timeframe by optimally utilizing the available resources. Among others, the arms acquisition needs to flow from a strong planning process that is presently constrained to bring in the required inter- and intra-service prioritization of weapons acquisition and ensure holistic development of national capability. The formulation of weapons systems` requirements. a critical stage of the acquisition cycle, which is presently carried out within the individual armed forces with inherent weaknesses. needs to be undertaken preferably by a dedicated and professional body. The accountability of acquisition also needs to be strengthened by bringing about a centralized, integrated and professional agency with the responsibility of ensuring timely acquisition.
Application of Digital Image Processing for Shape Characterization of Sand Particles
Laxman Poudel,Bhola Thapa,Bim Prasad Shrestha,Nabin Kumar Shrestha 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-
This part of research work is focused on defining sand particles shape using Digital Image Processing (DIP). Sand particles shape can be defined using geometrical structures which involves mathematics and its derivatives. Shape descriptor is utilized to define exactly the sand particles shape. It describes the region or boundary of sand particles. So study of sand shape using digital image processing with Fourier analysis gives an exact particles shape. This research utilizes nondestructive automation technique online or off-line based on using image processing. It is revealed that total 21 different shape of sand particles were identified each having different measures. Sand shapes were analyzed and processed using Charge Coupled Devices (CCD) camera, image processing Matrox Imaging Library (MIL) Software and in MatLab 1.5 platform. This new way of vision which cannot be revealed by eye can characterize particles shape easily. Research in shape similarity has a lot of challenges, some solutions and, and for same in use in different application.