Slung Load Amplification Detector

2017 ◽  
Author(s):  
Nandeesh Hiremath ◽  
Dhwanil Shukla ◽  
Emily Hale ◽  
Taylor Sparacello ◽  
Narayanan Komerath
Keyword(s):  
Wind Tunnel ◽  
Flight Speed ◽  
Dynamics Simulation ◽  
Test Cases ◽  
Specific Load ◽  
Top Down ◽  
Practical Test ◽  
Life Threatening ◽  
Wind Tunnel Data ◽  
Simulation Results

Externally slung loads and their mission applications are becoming more common on human and autonomously piloted air vehicles. Flight speed is often limited not by the performance envelope but by the danger of divergent load oscillations. Certifying this limiting speed for every load-vehicle combination, is a huge barrier to operations. The conservatism dictated by this uncertainty may itself be life-threatening in critical applications. Computing the dynamics of slung loads for a specific load/vehicle combination has been hindered by lack of knowledge on bluffbody aeromechanics. The prevailing top-down approach is to incorporate slung load aeromechanics calculations into large comprehensive aeromechanics codes for rotorcraft. We argue for a bottom-up approach. This allows on-the-fly system identification and dynamics simulation. The Slung Load Amplification Detector (SLAD) concept provides an on-board safety system to predict, detect, avoid and alleviate divergent oscillations. SLAD is based on a knowledge base derived from wind tunnel data and simulation results including canonical geometries, as well as practical shapes. Validation of simulation results against two practical test cases lends confidence. SLAD allows reliable distinction between pseudo and absolute divergence, permitting an increase of as much as 50% speed in safe flight speed, and guidance on active alleviation of oscillations.

Validation of CFD Modeling and Simulation of a Simplified Automotive Model

2015 ◽  
Vol 735 ◽  
pp. 319-325
Author(s):  
S. Mansor ◽  
N.A.R. Nik Mohd ◽  
C.W. Chung
Keyword(s):  
Wind Tunnel ◽  
Modeling And Simulation ◽  
Best Practice ◽  
Cfd Simulation ◽  
Wind Tunnel Test ◽  
Turnaround Time ◽  
Cfd Modeling ◽  
Design Changes ◽  
Wind Tunnel Data ◽  
Simulation Results

In the early design phase of automotive sector, the flow field around the vehicle is important in decision making on design changes. It would consume a lot of money and time for multiple prototypes development if adopt traditional testing method which is wind tunnel test. Thus, numerical method such as Computational Fluid Dynamics (CFD) simulation plays an important role here. It is very often simulation results been compared with wind tunnel data. However, with various mesh types, meshing methodology, discretization methods and different solver control options in CFD simulation, users may feel low confidence level with the generated simulation results. Thus, a robust modeling and simulation guideline which would help in accurate prediction should be developed due to the industry’s demand for accuracy when comparing CFD to wind tunnel results within short turnaround time. In this paper, a CFD modeling and simulation study was conducted on a simplified automotive model to validate with wind tunnel test results. The wind tunnel environment was reproduced in the simulation setup to include same boundary conditions. Meshing guidelines, turbulence model comparisons and also the best practice for solver setup with respect to accuracy will be presented. Overall, CFD modeling and simulation methods applied in this paper are able to validate the results from experiment accurately within small yaw ranges.

Comparison of free-flight and wind tunnel data for a generic fighterconfiguration

1982 ◽  
Author(s):  
G. WINCHENBACH ◽  
R. CHELEKIS ◽  
B. USELTON ◽  
W. HATHAWAY
Keyword(s):  
Wind Tunnel ◽  
Free Flight ◽  
Wind Tunnel Data

Stent Graft Placement in the Top-Down Direction for Treating Traumatic Intra-Abdominal Suprahepatic Inferior Vena Cava Rupture: A Case Report

2021 ◽  
pp. 152660282110250
Author(s):  
Yun Chul Park ◽  
Hyoung Ook Kim ◽  
Nam Yeol Yim ◽  
Byung Chan Lee ◽  
Chan Park ◽  
...  
Keyword(s):  
Case Report ◽  
Inferior Vena Cava ◽  
Stent Graft ◽  
Inferior Vena ◽  
Vena Cava ◽  
Endovascular Management ◽  
Top Down ◽  
Life Threatening ◽  
The Right ◽  
Suprahepatic Inferior Vena Cava

Purpose The treatment of suprahepatic inferior vena cava (IVC) ruptures results in high mortality rates due to difficulty in performing the surgical procedure. Here, we present a case of successful endovascular management of a life-threatening suprahepatic IVC rupture with top-down placement of a stent graft. Case Report A 33-year-old woman was involved in a traffic accident and presented to our emergency department due to unstable hemodynamics after blunt abdominal wall trauma. Computed tomography (CT) revealed massive extravasation of contrast agent from the suprahepatic IVC, which suggested traumatic suprahepatic IVC rupture. To seal the IVC, to salvage major hepatic veins, and to prevent migration of the stent graft into the right side of the heart after placement, an aortic cuff with a proximal hook was introduced in a top-down direction via the right internal jugular vein. After closure of the injured IVC, the patient’s hemodynamics improved, and additional laparotomy was performed. After 3 months of trauma care, the patient recovered and was discharged. Follow-up CT after 58 months showed a patent stent graft within the IVC. Conclusion Endovascular management with top-down placement of a stent graft is a viable option for emergent damage control in patients with life-threatening hemorrhage from IVC rupture.

scholarly journals An overview of X-38 Hypersonic Wind Tunnel data and comparison with numerical results

1997 ◽  
Author(s):  
Charles Campbell ◽  
Jose Caram ◽  
Scott Berry ◽  
Michael DiFulvio ◽  
Tom Horvath ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Numerical Results ◽  
Hypersonic Wind Tunnel ◽  
Wind Tunnel Data

Study on Engine Kinematics and Dynamics Simulation Based on COSMOSMotion

2012 ◽  
Vol 503-504 ◽  
pp. 731-734
Author(s):  
Xiao Xu Liu ◽  
Min Chen ◽  
Ai Hua Tang
Keyword(s):  
Virtual Prototype ◽  
Dynamics Simulation ◽  
Kinematics And Dynamics ◽  
Engine Model ◽  
Kinematics Simulation ◽  
Simulation Based ◽  
Calculation Results ◽  
Simulation Results ◽  
Dynamics Simulations

The engine model with 4 cylinders is built by SolidWorks, the kinematics and dynamics simulations of the engine virtual prototype are done by COSMOSMotion, the results of kinematics simulation are checked, there are very small errors between the simulation results and the calculation results according to formulas. The mainly results of dynamics simulation are given. The simulation result consists with the parameters of the engine.

The Influence of the Convective Terms Discretization Scheme on the Simulation Results of Architectural Numerical Wind Tunnel

2012 ◽  
Vol 204-208 ◽  
pp. 4884-4887
Author(s):  
Jian Feng Wu ◽  
Cai Hua Wang ◽  
Chang Li Song
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Building Structures ◽  
Discretization Scheme ◽  
Shape Coefficient ◽  
Fluent Software ◽  
Actual Operation ◽  
Simulation Results ◽  
Load Shape ◽  
Numerical Wind Tunnel Method

The numerical simulation of construction is to obtain the desired accuracy. It depends on the theoretical basis of the calculator and selection of the various important factors in the actual operation. For this problem, this paper adopting the current code for the design of building structures as the comparison standard, using the FLUENT software, taking the numerical simulation results of a high building’s wind load shape coefficient of for example, discussing the influence of four kinds of the convective terms discretization scheme, respectively the first-order upwind, the second order upwind , power law and Quadratic upwind interpolation for convective kinematics, on the simulation results of architectural numerical wind tunnel, provides the reference for the rational use of numerical wind tunnel method.

Dynamics Simulation and Analysis of Transition Stage of Tilt-Rotor Aircraft

2016 ◽  
Vol 842 ◽  
pp. 251-258 ◽  
Author(s):  
Muhammad Rafi Hadytama ◽  
Rianto A. Sasongko
Keyword(s):  
Dynamic Response ◽  
Equations Of Motion ◽  
Flight Dynamics ◽  
Dynamics Simulation ◽  
Tilt Rotor ◽  
Vertical Takeoff And Landing ◽  
Improved Stability ◽  
Simulation Results ◽  
Vtol Aircraft ◽  
Vertical Takeoff

This paper presents the flight dynamics simulation and analysis of a tilt-rotor vertical takeoff and landing (VTOL) aircraft on transition phase, that is conversion from vertical or hover to horizontal or level flight and vice versa. The model of the aircraft is derived from simplified equations of motion comprising the forces and moments working on the aircraft in the airplane's longitudinal plane of motion. This study focuses on the problem of the airplane's dynamic response during conversion phase, which gives an understanding about the flight characteristics of the vehicle. The understanding about the flight dynamics characteristics is important for the control system design phase. Some simulation results are given to provide better visualization about the behaviour of the tilt-rotor. The simulation results show that both transition phases are quite stable, although an improved stability can give better manoeuver and attitude handling. Improvement on the simulation model is also required to provide more accurate and realistic dynamic response of the vehicle.

The Study on Young's Modulus of Multilayered Cu/Ni Multilayered Nano Thin Films by Molecular Dynamics Simulation

2014 ◽  
Vol 513-517 ◽  
pp. 113-116
Author(s):  
Jen Ching Huang ◽  
Fu Jen Cheng ◽  
Chun Song Yang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Strain Rate ◽  
Young’S Modulus ◽  
Potential Function ◽  
Dynamics Simulation ◽  
System Temperature ◽  
Simulation Results

The Youngs modulus of multilayered nanothin films is an important property. This paper focused to investigate the Youngs Modulus of Multilayered Ni/Cu Multilayered nanoThin Films under different condition by Molecular Dynamics Simulation. The NVT ensemble and COMPASS potential function were employed in the simulation. The multilayered nanothin film contained the Ni and Cu thin films in sequence. From simulation results, it is found that the Youngs modulus of Cu/Ni multilayered nanothin film is different at different lattice orientations, temperatures and strain rate. After experiments, it can be found that the Youngs modulus of multilayered nanothin film in the plane (100) is highest. As thickness of the thin film and system temperature rises, Youngs modulus of multilayered nanothin film is reduced instead. And, the strain rate increases, the Youngs modulus of Cu/Ni multilayered nanothin film will also increase.

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