scholarly journals Aircraft Ditching Loads Simulation Tool

2015 ◽  
Vol 798 ◽  
pp. 531-535
Author(s):  
Antonino Bonanni ◽  
Lorenz Vandewaeter ◽  
Caroline Havill ◽  
Prin Kanyoo ◽  
Dominic Taunton ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Test Case ◽  
Simulation Tool ◽  
Lattice Method ◽  
Research Project ◽  
Dynamic Simulations ◽  
Proprietary Software ◽  
Steady Pressure ◽  
Doublet Lattice Method ◽  
Multi Phase

The present work presents a novel methodology developed for calculating the steady loads acting on aircraft structures in the event of ditching in water. It represents the preliminary result of Stirling Dynamics as part of a NATEP research project. The overall objective of the project is to expand the capabilities of the Stirling Dynamics proprietary software SD-GLOAD (originally designed for ground and crash loads dynamic simulations) to aircraft ditching simulations. The methodology presented in this paper employs a Doublet Lattice Method (DLM) to calculate the steady pressure distribution acting on the submerged parts of the ditching aircraft. The proposed methodology is validated against a higher-fidelity CFD multi-phase model for a selected test-case and several ditching conditions.

Further Refinement of the Subsonic Doublet-Lattice Method

1998 ◽  
Vol 35 (5) ◽  
pp. 720-727 ◽  
Author(s):  
William P. Rodden ◽  
Paul F. Taylor ◽  
Samuel C. McIntosh
Keyword(s):  
Lattice Method ◽  
Doublet Lattice Method

On the pressure distribution in multi-phase pipelines

2021 ◽  
pp. 58-61
Author(s):  
F.B. Ismayilova ◽  
Keyword(s):  
Mathematical Model ◽  
Pressure Distribution ◽  
Phase Transformations ◽  
Flow Regime ◽  
Exponential Rate ◽  
Technological Field ◽  
Saturated Mixture ◽  
Multi Phase

The results of investigations and measurements of actual pressure values carried out recently in technological-field pipelines show that the nature of pressure distribution in multi-phase pipelines differs from those in mono-phase ones. The paper analyzes the aspects affecting the pressure distribution in gas-saturated fluids in the presence of phase transformations. Considering the changes in compressibility of gas-saturated mixture, a mathematical model for pressure distribution through the length of pipeline has been developed. It was defined that depending on the compressibility ratio and flow regime, the pressure distribution in multi-phase pipeline decreases steadily at an exponential rate.

Cable JIP: A Research Project to Assess the Feasibility of a Semi-Static Electrical Subsea Cable for the Power Take-off from a TLP-type Floating Offshore Wind Turbine

2021 ◽  
Author(s):  
J. J. de Wilde ◽  
C. G. J. M. van der Nat ◽  
L.. Pots ◽  
L. B. de Vries ◽  
Q.. Liu
Keyword(s):  
Wind Turbine ◽  
Numerical Models ◽  
Electrical Power ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Power Cable ◽  
Test Case ◽  
Research Project ◽  
Floating Offshore Wind Turbine ◽  
Cost Of Energy

Abstract CABLE JIP research project in 2017-2019 was initiated with the aim of studying the feasibility of deploying a novel semi-static electrical cable for the power take-off from a TLP-type Floating Offshore Wind Turbine (FOWT). Today, expensive dynamic electrical cables are mainly used for the power take-off from demonstrator project FOWTs or from new FOWTs on the drawing board. For a TLP-type FOWT, the use of a semi-static electrical power cable instead of a fully dynamic electrical power cable (umbilical) is an attractive option to reduce the levelized cost of energy (LCoE). However, the electrical power cable in a dynamic offshore environment is vulnerable to failure, either at the floater side or at the seabed touchdown area. Moreover, the electrical power cable for power take-off is typically non-redundant, while the availability of the turbine(s) highly depends on this critical component to transport the produced power to the substation. The paper discusses the results of the CABLE JIP research project, with focus on the verification and calibration of the numerical models for the ULS and FLS assessment of the electrical power inter-array cable for a harsh weather test case with a TLP-type floating offshore wind turbine in 96.5 m water depth.

De Analfabetische Blik en de Geletterde Bril

2002 ◽  
Vol 68 ◽  
pp. 9-26 ◽  
Author(s):  
Jeanne Kurvers
Keyword(s):  
Young Children ◽  
Metalinguistic Awareness ◽  
Test Case ◽  
Writing Systems ◽  
Adult Readers ◽  
Research Project ◽  
Language Analysis ◽  
The One ◽  
Low Educated ◽  
Metalinguistic Knowledge

Until recently, studies about adults' metalinguistic knowledge nearly always dealt with adult readers. Since explanations about the development of children's metalinguistic knowledge are not conclusive about the influence of either (language) development or experience with written language. Adult illiterates form a nice test case for these contrasting hypotheses, since they are both experienced language users and inexperienced in the written code. Therefore, a research project was carried out to compare the metalinguistic knowledge of adult illiterates with another group of non-readers (young children) and with low-educated adult readers. The research project was carried out with 24 young pre-readers, 25 adult (true) illiterates and 23 adult readers with about four years of schooling. All groups were offered different tests of metalinguistic awareness on the phonological, lexical/semantic and discourse-level of language. Analysis of variance and posthoc analyses showed that, on the whole, there were hardly any differences between young children and all adults in the knowledge of linguistic entities (favouring the developmental hypotheses) while there were many significant differences between the no-nreaders on the one hand (both children and adults) and low-educated literates on the other hand. It is concluded that experience with writing systems plays a major role in triggering metalinguistic knowledge.

scholarly journals Numerical Optimization of a Stall Margin Enhancing Recirculation Channel for an Axial Compressor

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 88
Author(s):  
Motoyuki Kawase ◽  
Aldo Rona
Keyword(s):  
High Speed ◽  
High Performance ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Leading Edge ◽  
Navier Stokes ◽  
Test Case ◽  
Dynamic Simulations ◽  
Stall Margin ◽  
Casing Treatment

A proof of concept is provided by computational fluid dynamic simulations of a new recirculating type casing treatment. This treatment aims at extending the stable operating range of highly loaded axial compressors, so to improve the safety of sorties of high-speed, high-performance aircraft powered by high specific thrust engines. This casing treatment, featuring an axisymmetric recirculation channel, is evaluated on the NASA rotor 37 test case by steady and unsteady Reynolds Averaged Navier Stokes (RANS) simulations, using the realizable k-ε model. Flow blockage at the recirculation channel outlet was mitigated by chamfering the exit of the recirculation channel inner wall. The channel axial location from the rotor blade tip leading edge was optimized parametrically over the range −4.6% to 47.6% of the rotor tip axial chord c z . Locating the channel at 18.2% c z provided the best stall margin gain of approximately 5.5% compared to the untreated rotor. No rotor adiabatic efficiency was lost by the application of this casing treatment. The investigation into the flow structure with the recirculating channel gave a good insight into how the new casing treatment generates this benefit. The combination of stall margin gain at no rotor adiabatic efficiency loss makes this design attractive for applications to high-speed gas turbine engines.

Numerical Solutions of Nonsteady Two-Dimensional Transonic Flows

1979 ◽  
Vol 101 (3) ◽  
pp. 341-347 ◽  
Author(s):  
M. Couston ◽  
J. J. Angelini
Keyword(s):  
Numerical Solutions ◽  
Low Frequency ◽  
Two Dimensional ◽  
Lattice Method ◽  
Alternating Direction Implicit ◽  
Flow Problems ◽  
Present Procedure ◽  
Alternating Direction ◽  
Trailing Edge Flaps ◽  
Doublet Lattice Method

An alternating-direction implicit algorithm is applied to solve an improved formulation of the low-frequency, small-disturbance, two-dimensional potential equation. Linear solutions are presented for oscillating trailing edge flaps, plunging and pitching flat-plate airfoils, and compared with results obtained by a doublet-lattice-method. Nonlinear calculations for both steady and unsteady flow problems are then compared with results obtained by using the complete Euler equations. The present procedure allows one to solve complex aerodynamic problems, including flows with shock waves.

Modeling and Analysis of Piezoelectric Energy Harvesting From Aeroelastic Vibrations Using the Doublet-Lattice Method

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Carlos De Marqui ◽  
Wander G. R. Vieira ◽  
Alper Erturk ◽  
Daniel J. Inman
Keyword(s):  
Energy Source ◽  
Energy Harvesting ◽  
Frequency Domain ◽  
Electromechanical Coupling ◽  
Lattice Method ◽  
Modeling And Analysis ◽  
Piezoelectric Energy ◽  
Doublet Lattice Method ◽  
Aeroelastic Vibrations ◽  
Air Vehicles

Multifunctional structures are pointed out as an important technology for the design of aircraft with volume, mass, and energy source limitations such as unmanned air vehicles (UAVs) and micro air vehicles (MAVs). In addition to its primary function of bearing aerodynamic loads, the wing/spar structure of an UAV or a MAV with embedded piezoceramics can provide an extra electrical energy source based on the concept of vibration energy harvesting to power small and wireless electronic components. Aeroelastic vibrations of a lifting surface can be converted into electricity using piezoelectric transduction. In this paper, frequency-domain piezoaeroelastic modeling and analysis of a cantilevered platelike wing with embedded piezoceramics is presented for energy harvesting. The electromechanical finite-element plate model is based on the thin-plate (Kirchhoff) assumptions while the unsteady aerodynamic model uses the doublet-lattice method. The electromechanical and aerodynamic models are combined to obtain the piezoaeroelastic equations, which are solved using a p-k scheme that accounts for the electromechanical coupling. The evolution of the aerodynamic damping and the frequency of each mode are obtained with changing airflow speed for a given electrical circuit. Expressions for piezoaeroelastically coupled frequency response functions (voltage, current, and electrical power as well the vibratory motion) are also defined by combining flow excitation with harmonic base excitation. Hence, piezoaeroelastic evolution can be investigated in frequency domain for different airflow speeds and electrical boundary conditions.

Improving the Convergence of the Doublet-Lattice Method Through Tip Corrections

2001 ◽  
Vol 38 (4) ◽  
pp. 772-776 ◽  
Author(s):  
Myles L. Baker ◽  
William P. Rodden
Keyword(s):  
Lattice Method ◽  
Doublet Lattice Method
Sign in / Sign up

Export Citation Format

Share Document