Flutter parametric studies of cantilevered twin-engine transport type wing with and without winglet. Volume 2: Transonic and density effect investigations

Flutter characteristics of a cantilevered high aspect ratio wing with winglet were investigated. The configuration represented a current technology, twin engine airplane. Compressibility effects through transonic Mach numbers and a wide range of mass-density ratios were evaluated on a low speed and high speed model. Four flutter mechanisms were obtained from test, and analysis from various combinations of configuration parameters. It is shown that the coupling between wing tip vertical and chordwise motions have significant effect under some conditions. It is concluded that for the flutter model configurations studied, the winglet related flutter is amenable to the conventional flutter analysis techniques. The low speed model flutter and the high-speed model flutter results are described

Bhoi Khasi Compared to Standard Khasi

The paper briefly documents the Bhoi variety of Khasi, in comparison with the standard variety

Effects of winglet on transonic flutter characteristics of a cantilevered twin-engine-transport wing model

A transonic model and a low-speed model were flutter tested in the Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90. Transonic flutter boundaries were measured for 10 different model configurations, which included variations in wing fuel, nacelle pylon stiffness, and wingtip configuration. The winglet effects were evaluated by testing the transonic model, having a specific wing fuel and nacelle pylon stiffness, with each of three wingtips, a nonimal tip, a winglet, and a nominal tip ballasted to simulate the winglet mass. The addition of the winglet substantially reduced the flutter speed of the wing at transonic Mach numbers. The winglet effect was configuration-dependent and was primarily due to winglet aerodynamics rather than mass. Flutter analyses using modified strip-theory aerodynamics (experimentally weighted) correlated reasonably well with test results. The four transonic flutter mechanisms predicted by analysis were obtained experimentally. The analysis satisfactorily predicted the mass-density-ratio effects on subsonic flutter obtained using the low-speed model. Additional analyses were made to determine the flutter sensitivity to several parameters at transonic speeds

Unusual occurrence of two species and rare occurrence of one sepceis of neritic squids off MangaIore coast

Cephalopods have a wide distribution in the seas around India, although only a few of them form a fishery at some centres. At Mangalore, cephalopods comprising mainly of Loligo duvaucelii (90%), Sepia aculeata and S. pharaonis constitute about 5-10%(962 tonnes in 1988) of the total trawl catch

A Critique of Drexler Dark Matter

Drexler dark matter is an alternate approach to dark matter that assumes that highly relativistic protons trapped in the halo of the galaxies could account for the missing mass. We look at various energetics involved in such a scenario such as the energy required to produce such particles and the corresponding lifetimes. Also we look at the energy losses from synchrotron and inverse Compton scattering and their signatures. The Coulomb repulsive instability due to the excess charge around the galaxies is also calculated. The above results lead us to conclude that such a model for DM is unfeasible.Comment: 4 pages, 10 equation

Technology Integration (Task 20) Aeroservoelastic Modeling and Design Studies

The HSCT Flight Controls Group has developed longitudinal control laws, utilizing PTC aeroelastic flexible models to minimize aeroservoelastic interaction effects, for a number of flight conditions. The control law design process resulted in a higher order controller and utilized a large number of sensors distributed along the body for minimizing the flexibility effects. Processes were developed to implement these higher order control laws for performing the dynamic gust loads and flutter analyses. The processes and its validation were documented in Reference 2, for selected flight condition. The analytical results for additional flight conditions are presented in this document for further validation

A lexicostatistical study of the Khasian languages: Khasi, Pnar, Lyngngam, and War

This paper presents the results of lexicostatistical, glottochronological, and Bayesian phylogenetic analyses of a 200 word data set for Standard Khasi, Lyngngam, Pnar and War. Very few works have appeared on the subject of the internal classification of the Khasian branch of Austroasiatic, leaving the existing reference literature disappointingly incomplete. The present analysis supports both the strong identity of Khasian as a unitary branch, with an internally nested branching structure that fits neatly with known historical, geographical and linguistic facts. Additionally, lexically based dating methods suggest that the internal diversification of Khasian began roughly between 1500 and 2000 years ago.Copyright Information: Copyright for this paper vested in the authors. Released under Creative Commons Attribution Licens

Evaluation of Aeroservoelastic Effects on Flutter

This report presents work performed by The Boeing Company to satisfy the deliverable "Evaluation of aeroservoelastic Effects on Symmetric Flutter" for Subtask 7 of Reference 1. The objective of this report is to incorporate the improved methods for studying the effects of a closed-loop control system on the aeroservoelastic behavior of the airplane planned under NASA HSR technical Integration Task 20 work. Also, a preliminary evaluation of the existing pitch control laws on symmetric flutter of the TCA configuration was addressed."The goal is to develop an improved modeling methodology and perform design studies that account for the aero-structures-systems interaction effects

COMPARATIVE STUDY ON CARRIER OVERLAPPING PWM STRATEGIES FOR THREE PHASE FIVE LEVEL DIODE CLAMPED AND CASCADED INVERTERS

This paper proposes three Carrier Overlapping PWM (COPWM) methods that utilize the (CFD) control freedom degree of vertical offsets among carriers. They are: COPWM-A, COPWM-B, COPWM-C these three methods are simulated . This paper presents a comparative study of diode clamped and cascaded three phase five-level inverters based on sinusoidal PWM& modified space vector PWM control techniques. Performance analysis is based on the results of simulation study conducted on the operation of the multilevel inverters using MATLAB/ SIMULINK. For comparison purposes, non-overlapping phase disposition PWM (PD PWM) using SPWM and modified space vector PWM is also presented. The performance parameters chosen the work included fundamental output voltage and total harmonic distortion. . A hardware set up was developed for a single-phase 5-level cascaded inverter topology using constant pulses