Helicopter aircrew are exposed to high levels of whole-body vibration (WBV) in fight operations, which may degrade their ride comfort and performance the short term contribute some health issues long term. This paper presents latest development flight-test demonstration results an active seat mount system that is designed reduce helicopter WBV through cancellation N/rev peaks related main rotor speed. A prototype airworthy hardware has been developed based on a previous bench-top-test design...

Abstract Wind tunnel experiments were performed to evaluate the power coefficients of three vertical axis wind turbines ( VAWT s), namely, (a) conventional (two‐bladed troposkien shape), (b) novel 50% shifted shape‐vertical turbine (50% STS ‐ ), and (c) 100% . All had same height, swept area, NACA 0015 airfoil with chord length. During coefficient measurements for each one turbines, velocity was varied while rotation kept constant through rheostatic load adjustment. Two different rotations...

This article is focused on the development and characterization of highly controllable magnetorheological materials for stiffness damping control in semi-active applications. Two types are developed in-house: elastomer with soft base elastomer, fluid encapsulated regular namely fluid-elastomer. In both cases elastomers fluid-elastomers, samples evaluated using in-house-developed shear compression test rigs, which equipped electromagnets Hall effect sensors measuring magnetic field. These...

The development of the bench model a hybrid (rigid-flexible) morphing leading edge is presented in this paper. distinctive feature design centers on compounding fully rigid nose with flexible structure to create seamless edge. guarantees precise shape control aerodynamically critical region wing whereas allows for an increase both chord length and its camber. These improvements offer potential solutions many challenges reported literature about existing designs. In order evaluate feasibility...

Abstract The aerodynamic performance of three different configurations vertical axis wind turbines ( VAWT ), namely: (a) conventional Darrieus troposkein (based on designed by Sandia National Laboratories), (b) novel 50% STS ‐ (50% shifted‐troposkein‐shaped and (c) 100% were investigated numerically. An in‐house code, which combined the blade element theory BET ) vortex filament method VFM was used. main purpose this work to develop an code predict as well assess configurations. Simulation...

This article presents the development and evaluation of a proof-of-concept multiaxis actively controlled helicopter seat mount for aircrew whole-body vibration reduction. The is designed to be installed between floor supporting structure minimize impact on crashworthiness requirements seat. design involves multiple miniature force actuators counteract vibrations frame occupant transmitted from in three orthogonal directions. are by an adaptive feedforward filtered-x least mean square...

The in-flight performance of an in-house developed multi-axis actively controlled mount system for helicopter seats is presented in this paper. progression the development seat from its conceptual design to airworthy suitable flight demonstration explained. first evaluated using mannequins three different weight categories. evaluation performed uniaxially vertical and fore/aft directions, independently. In each case, acceleration measurements collected on a Bell-412 research are used as...

Helicopter aircrew are exposed to high levels of whole-body vibration (WBV) in fight operations, which may degrade their ride comfort and performance the short-term, contribute some health issues long-term. This paper presents latest development flight test demonstration results an active seat mount system that is designed reduce helicopter WBV through cancellation N/rev peaks related main rotor speed. A prototype airworthy hardware has been developed based on previous bench-top-test designs...

Two coupling schemes for fluid-structure interaction using the OpenFOAM structural solver sixDoF Rigid Body Motion are developed. The first scheme is developed by modifying baseline leapfrog weak to minimize lag between fluid and solvers. second a strong based on Crank-Nicolson method. two newly implemented compared through aeroelastic simulation of NACA 64A010 airfoil Benchmark Supercritical Wing. solutions obtained exhibit significantly lower sensitivity changes in time step size scheme....

Abstract This paper presents the experimental and numerical investigation of a single-axis replicate patented multi-axis active vibration isolation seat mount. Following design system, this single axis mount uses flexible elastomer support placed in parallel with an electromagnetic actuator. is designed to reduce N/rev harmonic helicopter using filtered-X least mean square (FXLMS)-based controller. To improve efficiency FXLMS controller for application, ISO-2631-1 Wk filter added. Employing...

In this paper, a pseudo three-dimensional computational fluid dynamics model of Sandia's 17-meter Vertical Axis Wind Turbine is implemented and validated against experimental data for Tip Speed Ratio 4.60. The Unsteady Reynolds Averaged Navier Stokes equations the Shear Stress Transport turbulence are used to assess performance turbine in conjunction with ANSYS CFX's rotating domain setup. pressure coefficient, normal coefficient tangential were as validation metrics. numerical results...

View Video Presentation: https://doi.org/10.2514/6.2021-1835.vid This paper presents the development and evaluation of an actively controlled multi-axis helicopter seat mount system for aircrew whole-body vibration mitigation applications. The is designed to be installed between floor supporting structure frame minimize impact on crashworthiness requirements seat. active was incorporate multiple miniature force actuators counteract vibrations transmitted from in three orthogonal directions....

Our objective in this paper is to develop and utilize a minimax principle for proving the existence of symmetric solutions stationary Navier-Stokes equations. Notwithstanding its application paper, our broad enough capture other types provided equation external force are compatible under family operations including but not limited being invariant by compact groups. The subset functions required be linear subspace, closed convex set suffices purpose.

Helicopter aircrew are exposed to high levels of Whole-Body Vibration (WBV) in fight operations, which may degrade their ride comfort and performance the short-term, contribute adverse health issues long-term.The Active Seat Mount technology, presented this paper, was developed reduce whole-body vibration helicopter through active cancellation N/rev peaks related main rotor speed.The latest development technology including structural redesign for integration into rear cabin, extensive tests...

Stationary data lend themselves well to the Fourier decomposition into harmonic components. Conversely, spectral characteristics of non-stationary vary with time, and hence do not generally admit application transform. In order investigate localized time-frequency data, notions instantaneous frequency amplitude are invoked. These concepts applied von Ka´rma´n vortex shedding observed in wake a self-sustained pitching airfoil. For this range Reynolds numbers (104 – 105), it has been reported...