scholarly journals Dynamic Stability Analysis of a Hydrofoiling Sailing Boat using CFD

2021 ◽  
Vol 6 (01) ◽  
pp. 58-72
Author(s):  
Alec Bagué ◽  
Joris Degroote ◽  
Toon Demeester ◽  
Evert Lataire
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Design Stage ◽  
Real Eigenvalue ◽  
Preliminary Design Stage ◽  
Operation Stability ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability ◽  
Interaction Strategy ◽  
Sailing Boat

Abstract. This paper describes the study of the dynamic stability of a hydrofoiling sailing boat called the “Goodall Design Foiling Viper”. The goal of Goodall Design is to make hydrofoiling accessible to a wider public, whereas it was previously reserved for professional sailors at the highest level of the sport. To allow for safe operation, stability is an essential characteristic of the boat. The aim of this work is to find a strategy to perform a dynamic stability analysis using computational fluid dynamics (CFD), which can be used in a preliminary design stage. This paper starts by establishing a theoretical framework to perform the dynamic stability analysis. A stability analysis has to be performed around an equilibrium state which depends on operating parameters such as speed, centre of gravity, etc. . A fluid-structure interaction strategy is applied to determine these equilibrium states. The last part discusses the stability characteristics of the Viper. The framework managed to assess the dynamic stability of the Viper and found 5 longitudinal eigenmodes: two complex conjugated pairs of eigenvalues and one real eigenvalue. It can be concluded that the boat was both statically and dynamically stable.

scholarly journals Conceptual design of an aircraft for Mars mission

2019 ◽  
Vol 91 (6) ◽  
pp. 886-892
Author(s):  
Agnieszka Kwiek
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Conceptual Design ◽  
Design Stage ◽  
Content Type ◽  
Mars Mission ◽  
Longitudinal Dynamic ◽  
Short Period ◽  
The Impact ◽  
Tailless Aircraft

Purpose The purpose of this paper is to present the results of a conceptual design of Martian aircraft. This study focuses on the aerodynamic and longitudinal dynamic stability analysis. The main research questions are as follows: Does a tailless aircraft configuration can be used for Martian aircraft? How to the short period characteristic can be improved by side plates modification? Design/methodology/approach Because of a conceptual design stage of this Martian aircraft, aerodynamic characterises were computed by the Panukl package by using the potential flow model. The longitudinal dynamic stability was computed by MATLAB code, and the derivatives computed by the SDSA software were used as the input data. Different aircraft configurations have been studied, including different wing’s aerofoils and configurations of the side plate. Findings This paper presents results of aerodynamic characteristics computations and longitudinal dynamic stability analysis. This paper shows that tailless aircraft configuration has potential to be used as Martian aircraft. Moreover, the study of the impact of side plates’ configurations on the longitudinal dynamic stability is presented. This investigation reveals that the most effective method to improve the short period damping ratio is to change the height of the bottom plate. Practical implications The presented result might be useful in case of further design of the aircrafts for the Mars mission and designing the aircrafts in a tailless configuration. Social implications It is considered by the human expedition that Mars is the most probable planet to explore. This paper presents the conceptual study of aircraft which can be used to take the high-resolution pictures of the surface of Mars, which can be crucial to find the right place to establish a potential Martian base. Originality/value Most of aircrafts proposed for the Mars mission are designed in a configuration with a classic tail; this paper shows a preliminary calculation of the tailless Martian aircraft. Moreover, this paper shows the results of a dynamic stability analysis, where similar papers about aircrafts for the Mars mission do not show such outcomes, especially in the case of the tailless configuration. Moreover, this paper presents the results of the dynamic stability analysis of tailless aircraft with different configurations of the side plates.

scholarly journals CFD Investigation into Seakeeping Performance of a Training Ship

CFD letters ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 19-32
Author(s):  
Ahmad Fitriadhy ◽  
Syarifuddin Dewa ◽  
Nurul Aqilah Mansor ◽  
Nur Amira Adam ◽  
Ng Cheng Yee ◽  
...  
Keyword(s):  
Safety Assessment ◽  
Scale Model ◽  
Design Stage ◽  
Preliminary Design ◽  
Reliable Prediction ◽  
Subsequent Increase ◽  
Following Seas ◽  
Seakeeping Performance ◽  
Preliminary Design Stage ◽  
Computational Fluid Dynamics Cfd

The numerous ship accidents at sea have usually resulted in tremendous loss and casualties. To prevent such disastrous accidents, a comprehensive investigation into reliable prediction of seakeeping performance of a ship is necessarily required. This paper presents computational fluid dynamics (CFD) analysis on seakeeping performance of a training ship (full scale model) quantified through a Response of Amplitude Operators (RAO) for heave and pitch motions. The effects of wavelengths, wave directions and ship forward velocities have been accordingly taken into account. In general, the results revealed that the shorter wavelengths (l/L ? 1.0) have insignificant effect to the heave and pitch motions performance of the training ship, which means that the ship has good seakeeping behavior. However, the further increase of wavelength was proportional with the increase of RAO for her heave and pitch motions; whilst it may lead to degrade her seakeeping quality. In addition, the vertical motions behavior in the following-seas dealt with higher RAO as compared with case of the head-seas condition. Similarly, the subsequent increase of the ship forward velocity was prone to relatively increase of the RAO for her heave and pitch motions especially at l/L ? 2.0. It was merely concluded that this seakeeping prediction using CFD approach provides useful outcomes in the preliminary design stage for safety assessment of the training ship navigation during sailing.

scholarly journals Implicit Subspace Iteration to Improve the Stability Analysis in Grinding Processes

2020 ◽  
Vol 10 (22) ◽  
pp. 8203 ◽  
Author(s):  
Jorge Alvarez ◽  
Mikel Zatarain ◽  
David Barrenetxea ◽  
Jose Ignacio Marquinez ◽  
Borja Izquierdo
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Time Domain ◽  
Grinding Processes ◽  
Subspace Iteration ◽  
Efficient Calculation ◽  
Chatter Vibrations ◽  
Stability Maps ◽  
Iteration Methods ◽  
The Stability

An alternative method is devised for calculating dynamic stability maps in cylindrical and centerless infeed grinding processes. The method is based on the application of the Floquet theorem by repeated time integrations. Without the need of building the transition matrix, this is the most efficient calculation in terms of computation effort compared to previously presented time-domain stability analysis methods (semi-discretization or time-domain simulations). In the analyzed cases, subspace iteration has been up to 130 times faster. One of the advantages of these time-domain methods to the detriment of frequency domain ones is that they can analyze the stability of regenerative chatter with the application of variable workpiece speed, a well-known technique to avoid chatter vibrations in grinding processes so the optimal combination of amplitude and frequency can be selected. Subspace iteration methods also deal with this analysis, providing an efficient solution between 27 and 47 times faster than the abovementioned methods. Validation of this method has been carried out by comparing its accuracy with previous published methods such as semi-discretization, frequency and time-domain simulations, obtaining good correlation in the results of the dynamic stability maps and the instability reduction ratio maps due to the application of variable speed.

The Design and Development of the Aerodynamic Engineering Prediction Software for Aircrafts

2014 ◽  
Vol 543-547 ◽  
pp. 3136-3140
Author(s):  
Di Liang ◽  
Sheng Jing Tang
Keyword(s):  
Wind Tunnel Test ◽  
Aircraft Design ◽  
Aerodynamic Characteristics ◽  
Black Box ◽  
Design Stage ◽  
Preliminary Design ◽  
Preliminary Design Stage ◽  
Box Structure ◽  
Computational Fluid Dynamics Cfd ◽  
Calculation Module

Aerodynamic analysis and calculation are very important parts in the aircraft design, and aerodynamic engineering prediction is widely used in the aircraft preliminary design stage. However, traditional aerodynamic engineering prediction causes heavy computation and is time-consuming. The developed software such as DATCOM has the disadvantages of complicated operation and black box structure. To overcome the disadvantages above, we develop the software for aerodynamic engineering prediction based on the aerodynamic characteristics and prediction for aircrafts. There are three parts in this software which are database, calculation module and user interface. The software is verified by a numerical example of one aircraft, and compares with the data of Computational Fluid Dynamics (CFD) and the wind tunnel test. The results show that the calculated results of the aerodynamic engineering prediction and CFD are basically consistent, and the software is able to meet the accuracy demand in the preliminary design phase of the aircraft.

Dynamic Stability Analysis of the Tower Structure of Construction Elevators

2013 ◽  
Vol 459 ◽  
pp. 646-649
Author(s):  
Xian Rong Qin ◽  
Ying Hong ◽  
Peng Yue ◽  
Qing Zhang ◽  
Yuan Tao Sun
Keyword(s):  
Stability Analysis ◽  
Stress Field ◽  
Dynamic Stability ◽  
Transient Analysis ◽  
Stress Effect ◽  
Construction Process ◽  
Moving Loads ◽  
Eigenvalue Method ◽  
Tower Structure ◽  
The Stability

This paper proposed a method of dynamic stability analysis for the tower structure of construction elevators based on dynamic eigenvalue method. The method employed the time frozen formulation to model the problem, and the stress field from transient analysis was utilized to simulate the pre-stress effect of buckling analysis. The proposed method was applied to estimate the dynamic stability of the tower structure of construction elevators under moving loads, and the results suggest that high coefficients of lateral load and inclined tower structure will dramatically reduce the stability of the elevator in the construction process.

Dynamic Stability Analysis of Defective Piles under Vertical Harmonic Load

2013 ◽  
Vol 477-478 ◽  
pp. 592-595
Author(s):  
Xian Guang Ni
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Critical Frequency ◽  
Harmonic Load ◽  
Heterogeneous Soil ◽  
Engineering Problems ◽  
Practical Engineering ◽  
The Stability ◽  
Dynamical Function

We established the computational mode for defective piles based on practical engineering problems,and studied the stability of the defective pile in the heterogeneous soil under vertical harmonic loads. We established the dynamical function based on the principle of Energy and Hamilton, and abtained the expressions of critical frequency of defective piles.The results show that, the instability of the defective piles relate to the degree of defect and the location of defect.

Effect of Aerodynamic Loads on Dynamic Stability of Slender Launch Vehicle Subjected to an End Rocket Thrust

2002 ◽  
Author(s):  
Tsukasa Ohshima ◽  
Yoshihiko Sugiyama
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Longitudinal Axis ◽  
Launch Vehicle ◽  
Aerodynamic Load ◽  
Aerodynamic Loads ◽  
Eigen Values ◽  
Rocket Thrust ◽  
The Stability ◽  
Free Beam

This paper deals with dynamic stability of a slender launch vehicle subjected to aerodynamic loads and an end rocket thrust. The flight vehicle is simplified into a uniform free-free beam subjected to an end follower thrust. Two types of aerodynamic loads are assumed in the stability analysis. Firstly, it is assumed that two concentrated aerodynamic loads act on the flight body at its nose and tail. Secondly, to take account of effect of unsteady flow due to motion of a flexible flight body, aerodynamic load is estimated by the slender body approximation. Extended Hamilton’s principle is applied to the considered beam for deriving the equation of motion. Application of FEM yields standard eigen-value problem. Dynamic stability of the beam is determined by the sign of the real part of the complex eigen-values. If aerodynamic loads are concentrated loads that act on the flight body at its nose and tail, the flutter thrust decreases by about 10% in comparison with the flutter thrust of free-free beam subjected only to an end follower thrust. If aerodynamic loads are distributed along the longitudinal axis of the flight body, the flutter thrust decreases by about 70% in comparison with the flutter thrust of free-free beam under an end follower thrust. It is found that the flutter thrust is reduced considerably if the aerodynamic loads are taken into account in addition to an end rocket thrust in the stability analysis of slender rocket vehicle.

Advanced Dynamic Stability Analysis

2009 ◽  
Author(s):  
Hammam O. Zeitoun ◽  
Knut To̸rnes ◽  
John Li ◽  
Simon Wong ◽  
Ralph Brevet ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Dynamic Response ◽  
Dynamic Stability ◽  
Structural Response ◽  
Force Balance ◽  
Finite Elements Analysis ◽  
Interaction Modelling ◽  
Advanced Analysis ◽  
The Stability ◽  
Subsea Pipelines

Several design approaches can be used to analyse the stability of subsea pipelines [1]. These design approaches vary in complexity and range between simple force-balance calculations to more comprehensive dynamic finite element simulations. The latter may be used to more accurately simulate the dynamic response of subsea pipelines exposed to waves and steady current kinematics, and can be applied to optimise pipeline stabilisation requirements. This paper describes the use of state-of-the-art transient dynamic finite elements analysis techniques to analyse pipeline dynamic response. The described techniques cover the various aspects of dynamic stability analysis, including: • Generation of hydrodynamic forces on subsea pipelines resulting from surface waves or internal waves. • Modelling of pipe-soil interaction. • Modelling of pipeline structural response. The paper discusses the advantages of using dynamic stability analysis for assessing the pipeline response, presents advanced analysis and modelling capabilities which have been applied and compares this to previously published knowledge. Further potential FE applications are also described which extends the applicability of the described model to analyse the pipeline response to a combined buckling and stability problem or to assess the dynamic response of a pipeline on a rough seabed.

Tip-Over Stability Analysis of Mobile Boom Cranes With Swinging Payloads

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Andreas Rauch ◽  
William Singhose ◽  
Daichi Fujioka ◽  
Taft Jones
Keyword(s):  
Stability Analysis ◽  
Dynamic Analysis ◽  
Dynamic Stability ◽  
Dynamic Method ◽  
Static Stability ◽  
Multibody Simulation ◽  
The World ◽  
The Stability ◽  
Boom Crane ◽  
Mobile Base

Mobile boom cranes are used throughout the world to perform important and dangerous manipulation tasks. The usefulness of these cranes is greatly improved if they can utilize their mobile base when they lift and transfer a payload. However, crane motion induces payload swing. The tip-over stability is degraded by the payload oscillations. This paper presents a process for conducting a stability analysis of such cranes. As a first step, a static stability analysis is conducted to provide basic insights into the effects of the payload weight and crane configuration. Then, a semi-dynamic method is used to account for payload swing. The results of a full-dynamic stability analysis using a multibody simulation of a boom crane are then compared to the outcomes of the simpler approaches. The comparison reveals that the simple semi-dynamic analysis provides good approximations for the tip-over stability properties. The results of the stability analyses are verified by experiments. The analysis in this paper provides useful guidance for the practical tip-over stability analysis of mobile boom cranes and motivates the need to control payload oscillation.

Yaw Stability Analysis for UiTM's BWB Baseline-II UAV E-4

2013 ◽  
Vol 393 ◽  
pp. 323-328 ◽  
Author(s):  
Firdaus Mohamad ◽  
Wirachman Wisnoe ◽  
Rizal E.M. Nasir ◽  
Khairul Imran Sainan ◽  
Norhisyam Jenal
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stability Analysis ◽  
Mach Number ◽  
Deflection Angle ◽  
Rolling Moment ◽  
Yaw Stability ◽  
Directional Motion ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability

This paper presents a study about yaw stability analysis for UiTMs Blended-Wing-Body (BWB) Baseline-II E-4. This aircraft is equipped with split drag flaps in order to perform directional motion. One of the split drag flaps will be deflected to generate yawing moment. This yawing moment is generated through the drag that is produced upon deflection of flaps. The study was carried out using Computational Fluid Dynamics (CFD) for various sideslip angles (β) and various flaps deflection angle (δT). The simulation was conducted at 0.1 Mach number (35 m/s) and results in terms of coefficient such yawing and rolling moment are tabulated in order to determine the stability of the aircraft. The result reveals that the aircraft is directionally unstable. This is as expected because the aircraft does not have any vertical tail configuration to provide the yawing moment. However, high deflection of split flaps can still generate adequate restoring moment for the aircraft.

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