Department of Mechanical Engineering

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

This paper presents the results of an analytical study aimed at predicting the aeromechanical stability of a helicopter in ground resonance, with the inclusion of aerodynamic forces. The theoretical results are found to be in good agreement with the experimental results, available in the literature, indicating that the coupled rotor/fuselage system can be represented by a reasonably simple mathematical model. © 1985 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

World University root node

Journal of Aircraft

Coupled helicopter rotor/body aeromechanical stability comparison oftheoretical and experimental results

The paper presents a method for formulating finite state unsteady aerodynamic models in the time domain from frequency domain unsteady aerodynamics. The method is based on recognizing that the lift deficiency function represents an aerodynamic transfer function and utilizes the Bode plot technique, used in control systems engineering, to construct approximation to the lift deficiency function. Indicial response functions for both fixed wing and rotary wing applications are obtained, using these finite state unsteady aerodynamic models. It is shown that the rotary wind indicial response function is oscillatory and thus it is fundamentally different when compared to the fixed wing indicial response function which is nonoscillatory. Certain aspects of the finite state aerodynamic model are demonstrated by applying it to the flapping dynamics of an articulated helicopter rotor blade.

FINITE STATE MODELLING OF UNSTEADY AERODYNAMICS AND ITS APPLICATION TO A ROTOR DYNAMIC PROBLEM.

Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

AEROMECHANICAL STABILITY ANALYSIS OF A MULTIROTOR VEHICLE MODEL REPRESENTING A HYBRID HEAVY LIFT AIRSHIP (HHLA).

This report presents a set of governing coupled differential equations for a model of a hybrid aircraft. The model consists of multiple rotor systems connected by an elastic interconnecting structure, with options to add any combination of or all of the following components: thrusters, a buoyant hull, and an underslung weight. The dynamic equations are written for the individual blade with hub motions, for the rigid body motions of the whole model, and also for the flexible modes of the interconnecting structure. One of the purposes of this study is to serve as the basis of a numerical study aimed at determining the aeroelastic stability and structural response characteristics of a Hybrid Heavy Lift Airship (HHLA). It is also expected that the formulation be applicable to analyzing stability and response of dual rotor helicopters such as a Heavy Helicopter (HLH). Furthermore, the model is capable of representing coupled rotor/body aeromechanical problems of single rotor helicopters.

NASA Contractor Reports

AEROELASTIC EFFECTS IN MULTI-ROTOR VEHICLES WITH APPLICATION TO A HYBRID HEAVY LIFT SYSTEM. PART I: FORMULATION OF EQUATIONS OF MOTION.

AIAA Journal

Effect of pulsed slot suction on a turbulent boundary layer

Journal of Sound and Vibration

Authors' reply

The non-linear equations of motion of a rotating blade undergoing extensional and flapwise bending vibration are derived, including non-linearities up to O (ε3). The strain-displacement relationship derived is compared with expressions derived by earlier investigators and the errors and the approximations made in some of those are brought out. The equations of motion are solved under the inextensionality condition to obtain the influence of the amplitude on the fundamental flapwise natural frequency of the rotating blade. It is found that large finite amplitudes have a softening effect on the flapwise frequency and that this influence becomes stronger at higher speeds of rotation. © 1982 Academic Press Inc.

Non-linear flapping vibrations of rotating blades

Time series, from a narrow point of view, is a sequence of observations on a stochastic process made at discrete and equally spaced time intervals. Its future behavior can be predicted by identifying, fitting, and confirming a mathematical model. In this paper, time series analysis is applied to problems concerning runwayinduced vibrations of an aircraft. A simple mathematical model based on this technique is fitted to obtain the impulse response coefficients of an aircraft system considered as a whole for a particular type of operation. Using this model, the output which is the aircraft response can be obtained with lesser computation time for any runway profile as the input. © 1981 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

Stochastic modeling of an aircraft traversing a runway using time series analysis

On the axial vibrations of rotating bars

Thick boundary layers at zero pressure gradient are produced by generators kept along the leading edge of a flat surface and sustained by roughness elements distributed over the surface. Size, shape and spacing of the generators, distribution of the roughness elements and the roughness fetch are varied and the mean velocity profile measured at various locations. The results obtained show that layer thicknesses of about 25 cm can be obtained in a relatively short fetch of 1 m and that mean velocity profiles corresponding to both rural and urban terrain conditions can be simulated.