AERODYNAMIC LIFT FORCES ON MULTIHULLED MARINE VEHICLES

2021 ◽  
Vol 152 (A2) ◽  
Author(s):  
A G W Williams ◽  
M Collu ◽  
M H Patel
Keyword(s):  
High Speed ◽  
Vehicle Stability ◽  
Aerodynamic Design ◽  
Forward Motion ◽  
Marine Vehicles ◽  
Marine Transport ◽  
Stability Model ◽  
Lift Forces ◽  
High Payload ◽  
Aerodynamic Lift

The need for high-speed high-payload craft has led to considerable efforts within the marine transport industry towards a vehicle capable of bridging the gap between conventional ships and aircraft. One such concept uses the forward motion of the craft to create aerodynamic lift forces on a wing-like superstructure and hence, reduce the displacement and skin friction. This paper addresses the specific aerodynamic design of multihull for optimal lift production and shows that significant efficiency can be achieved through careful shaping of a ducted hull, with lift-to-drag ratios of nearly 50 for a complete aerodynamic hull configuration. Further analysis is carried out using a hybrid vehicle stability model to determine the effect of such aerodynamic alleviation on a theoretical planing hull. It is found that the resistance can be halved for a fifty metre, three hundred tonne vehicle with aerodynamic alleviation travelling at 70 knots. Results are presented for a candidate vessel.

Saskatchewan Highways and Transportation Reduced Tire Pressure Initiative

1997 ◽  
Vol 1589 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Thomas L. Davies ◽  
Tami F. Wall ◽  
Allan Carpentier
Keyword(s):  
High Speed ◽  
Membrane Surface ◽  
Vehicle Stability ◽  
Road Maintenance ◽  
Long Term Effects ◽  
Tire Pressure ◽  
Reduced Pressure ◽  
Maintenance Costs ◽  
Short And Long Term

After examination of the research carried out by other agencies, Saskatchewan Highways and Transportation (SHT) embarked on an initiative to adapt low tire pressure technologies to the province's needs and environment. The focus of the initiative was to explore several technical questions from SHT's perspective: (a) Can low tire pressures be used to increase truck weights from secondary to primary without increasing road maintenance costs on thin membrane surface roads? (b) What are the short- and long-term effects of tire heating under high-speed/high-deflection constant reduced pressure (CRP) operations in a Saskatchewan environment? (c) What effects do lower tire pressures have on vehicle stability at highway speeds? To date, significant opportunities have been noted on local hauls (less than 30 min loaded at highway speeds) for CRP operation and long primary highway hauls that begin or end in relatively short secondary highway sections that limit vehicle weight allowed for the whole trip for central tire inflation technology. The background and environment for the initiative and the investigations and demonstrations envisioned and undertaken are briefly outlined.

Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Alptunc Comak ◽  
Orkun Ozsahin ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Machine Tools ◽  
High Speed ◽  
End Mill ◽  
Spindle Shaft ◽  
Milling Operations ◽  
Stability Model ◽  
Principal Directions ◽  
The Stability ◽  
Rotating Coordinates

High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in rotating frame by considering the time- and speed-dependent, periodic dynamic milling system. The stability of the system is solved in both frequency and semidiscrete time domain. It is shown that the stability pockets differ significantly when the rotating dynamics of the asymmetric tools are considered. The proposed stability model has been experimentally validated in high-speed milling of an aluminum alloy with a two-fluted, asymmetric helical end mill.

Exploring research on high-speed vehicle attitude control with plasma virtual flap manipulation

2018 ◽  
Vol 233 (10) ◽  
pp. 3627-3634
Author(s):  
Wang Xin ◽  
Yan Jie ◽  
Zhang Yerong
Keyword(s):  
Attitude Control ◽  
High Speed ◽  
Long Duration ◽  
Aerodynamic Control ◽  
Control Authority ◽  
Attitude Controller ◽  
Lift And Drag ◽  
Cruise Flight ◽  
Aerodynamic Lift ◽  
High Speed Vehicle

This work provides an attitude solution for a high-speed vehicle using plasma aerodynamic control called “plasma virtual flap” manipulation. This paper describes the concept of using plasma active control as plasma virtual flap for off-design attitude manipulation problem. Design of an attitude controller considering plasma aerodynamic effects for the high-speed vehicle is presented. The aerodynamic lift and drag force features in the high speed, long duration cruise flight with plasma actuator effect are introduced, where the estimated models and attitude controller are established. This paper documents the development and capabilities of plasma virtual flap attitude control authority. Simulation results are presented to exhibit the effectiveness of the proposed method.

scholarly journals Simulation of marine vehicles operation in the state of wind and wave conditions

2021 ◽  
pp. 191-199
Author(s):  
А.А. Карпенко
Keyword(s):  
Supply Chain ◽  
Simulation Model ◽  
Transport System ◽  
Wind Wave ◽  
Supply Chain System ◽  
Chain System ◽  
Marine Vehicles ◽  
Marine Transport ◽  
The Impact ◽  
The City

Эксплуатация морского транспорта подвержена влиянию множества факторов, учет которого требует высокой трудоемкости. Как правило, моделирование морских транспортных систем, выступающих в роли связующего звена различных экономических процессов, производится на стадии предпроектной разработки. На этой стадии, помимо прочего, необходимо оценить влияние на проектируемую систему не только детерминированных, но и стохастических процессов. В данной работе описан алгоритм учета влияния ветро-волновых режимов морских участков на эксплуатацию морских транспортных судов. Данный алгоритм реализован на примере модели системы поставок сжиженного природного газа (СПГ) морским транспортом потребителям г. Мурманск. Научной новизной данной работы является комплексный подход к логико-математическому описанию эксплуатации морских транспортных средств. Этот подход включает в себя моделирование эксплуатации судна на базе агентного подхода, моделирование ветро-волновых режимов на основе анализа временных рядов и стохастических экспериментов и определение скорости движения судна на основе эмпирико-статистических формул расчета скорости судна и теории гидродинамики судна. В ходе выполнения данной работы была построена имитационная модель поставок СПГ в г. Мурманск морским транспортом. Результаты прогонов этой модели были верифицированы на основе технико-экономического обоснования АО «ЦНИИМФ». Алгоритм построения имитационной модели, описанный в данной работе, может быть применен для имитационного моделирования морских транспортных систем с различными целями функционирования. Marine transport operation is affected by a lot of factors taking into account of which requires a high laboriousness. In most cases modelling of marine transport operation as a link in various economic processes is performed at the pre-design development stage. By the way, evaluation of the impact of both deterministic and stochastic processes on the designed system is necessary at this stage. Evaluation of transport system efficiency based on pre-formed system of criteria is in progress at this stage. This paper describes an algorithm for modeling the operation of marine vessels taking into account wind-wave regime of sea areas. This algorithm is implemented by the model of liquified natural gas (LNG) supply chain system by marine transport to consumers of the city of Murmansk. Scientific novelty of this paper is a complex approach to logical-mathematical description of marine vehicles exploitation. This approach consists of agent-based simulation of vessel exploitation, modelling of wind-wave regimes by means of time series analysis and stochastic modelling and the speed determination of the vessel movement based on the empirical-statistical formulas for calculating the speed of the vessel and the theory of vessel hydrodynamics. During this research simulation model LNG supply chain system by marine transport to consumers of the city of Murmansk was developed. The results of the model have been verified by the feasibility study performed by CNIIMF JSC. The algorithm for constructing simulation model described in this paper could be implemented in modelling of marine transport system for various purposes.

Study on high-speed stability of automobile based on aerodynamic lift feedback

2021 ◽  
Vol 10 (3) ◽  
pp. 293
Author(s):  
Shuichang Liu ◽  
Fengzhao Mao ◽  
Qibo Lin ◽  
Ye Xiao ◽  
Jiaqi Shi ◽  
...  
Keyword(s):  
High Speed ◽  
Speed Stability ◽  
Aerodynamic Lift

Prediction of drag and lift forces of a high-speed vessel at full scale by CFD-based GEOSIM method

2022 ◽  
pp. 147509022110707
Author(s):  
Ugur Can ◽  
Sakir Bal
Keyword(s):  
High Speed ◽  
Full Scale ◽  
Navier Stokes ◽  
Drag Forces ◽  
Fluid Body ◽  
Unsteady Rans ◽  
Lift Forces ◽  
Drag And Lift ◽  
Lift And Drag ◽  
Model Family

In this study, it was aimed to obtain an accurate extrapolation method to compute lift and drag forces of high-speed vessels at full-scale by using CFD (Computational Fluid Dynamics) based GEOSIM (GEOmetrically SIMilar) method which is valid for both fully planing and semi-planing regimes. Athena R/V 5365 bare hull form with a skeg which is a semi-displacement type of high-speed vessel was selected with a model family for hydrodynamic analyses under captive and free to sinkage/trim conditions. Total drag and lift forces have been computed for a generated GEOSIM family of this form at three different model scales and full-scale for Fr = 0.8 by an unsteady RANS (Reynolds Averaged Navier–Stokes) solver. k–ε turbulence model was used to simulate the turbulent flow around the hulls, and both DFBI (Dynamic Fluid Body Interaction) and overset mesh technique were carried out to model the heave and pitch motions under free to sinkage/trim condition. The computational results of the model family were used to get “drag-lift ratio curve” for Athena hull at a fixed Fr number and so the corresponding results at full scale were predicted by extrapolating those of model scales in the form of a non-dimensional ratios of drag-lift forces. Then the extrapolated full-scale results calculated by modified GEOSIM method were compared with those of full-scale CFD and obtained by Froude extrapolation technique. The modified GEOSIM method has been found to be successful to compute the main forces (lift and drag) acting on high-speed vessels as a single coefficient at full scale. The method also works accurately both under fully and semi-planing conditions.

Study on high-speed stability of automobile based on aerodynamic lift feedback

2021 ◽  
Vol 10 (3) ◽  
pp. 293
Author(s):  
Yong Zhang ◽  
Jiaqi Shi ◽  
Ye Xiao ◽  
Qibo Lin ◽  
Fengzhao Mao ◽  
...  
Keyword(s):  
High Speed ◽  
Speed Stability ◽  
Aerodynamic Lift

Comparative Assessment of Rule-Based Design on the Pressures and Resulting Scantlings of High Speed Powercrafts

2020 ◽  
Author(s):  
Jean-Baptiste R.G. Souppez ◽  
Ermina Begovic ◽  
Pradeep Sensharma ◽  
Fuhua Wang ◽  
Anders Rosén
Keyword(s):  
High Speed ◽  
Future Trends ◽  
Rule Based ◽  
Marine Vehicles ◽  
Current State ◽  
Regulatory Bodies ◽  
1960S And 1970S ◽  
The 1960S ◽  
Design Case Study

The rules and regulations inherent to the design pressures and scantlings of high-speed powercrafts are numerous, and regularly reviewed. Recently, the new ISO 12215-5:2019 made notable changes to the way high-speed crafts are analysed, including extending the acceleration experienced up to 8 g in certain circumstances. Nevertheless, despite the multiple iterations and variety of regulatory bodies, the seminal work undertaken on planing crafts throughout the 1960s and 1970s remains the foundation of any rule-based design requirement. Consequently, this paper investigates an array of recently published rules though a comparative design case study, the current state-of-the-art across a number of regulations, and the ultimate impact on scantlings. The study reveals that, despite divergence in intermediate calculations and assumptions, similar requirements are ultimately achieved. Eventually, discussion on the comparison undertaken and future trends in high-speed marine vehicles is provided, tackling the relevance of classical planing theory in light of contemporary innovations.

scholarly journals Simulation analysis of efficiency and stability for vehicle’s ABS control on combined steering and braking maneuvers

2019 ◽  
Vol 272 ◽  
pp. 01024 ◽  
Author(s):  
Feng YU ◽  
Jun XIE
Keyword(s):  
High Speed ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Simulation Analysis ◽  
Stability Control ◽  
Vehicle Stability ◽  
Slip Ratio ◽  
Braking Performance ◽  
Braking System ◽  
The Stability

Eight degrees of freedom vehicle model was established. Using the method of fuzzy control, the ABS control algorithm was designed based on slip ratio. Simulation analysis was done at speed of 15m/s, 20m/s, 25m/s under turning braking. The results show that the vehicle braking performance and vehicle stability at middle or low speed was improved by using the ABS controller, but qualitative analysis shows that phenomenon of vehicle instability was appeared at high-speed conditions. The turning braking stability under ABS controller was judged quantificationally by the stability judging formula. The results show that the requirements of stability control could not meet with only Anti-lock Braking System.

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