The Interpretation of Results from Tank Tests on 12M Yachts

1987 ◽  
Author(s):  
Ian Campbell ◽  
Andrew Claughton
Keyword(s):  
Performance Prediction ◽  
Measurement Techniques ◽  
Reliable Data ◽  
Full Scale ◽  
Flow Visualisation ◽  
Measurement Systems ◽  
Components Of Resistance ◽  
Tank Test ◽  
Interpretation Of Results

Current Wolfson Unit tank test techniques are described and results presented that demonstrate how reliable data can be obtained from yacht models using simple equipment and measurement systems. The results presented are from models of 12m Yachts tested at both 1:10 and 1:4 scale. The correlation with full scale performance is shown for a 12m Yacht with a conventional keel. The induced and heeled components of resistance, obtained from tests at both scales, are compared for both the conventional and a winged keel. The interpretation of various characteristics in the tank data and the use of flow visualisation and measurement techniques are discussed. Scaling problems are considered and also shown is the influence of sail coefficients on the performance prediction for a 12m Yacht.

scholarly journals Comparative Accuracy Analysis of Truck Weight Measurement Techniques

2021 ◽  
Vol 11 (2) ◽  
pp. 745
Author(s):  
Sylwia Stawska ◽  
Jacek Chmielewski ◽  
Magdalena Bacharz ◽  
Kamil Bacharz ◽  
Andrzej Nowak
Keyword(s):  
Measurement Techniques ◽  
Highway Traffic ◽  
Highway Infrastructure ◽  
Measurement Systems ◽  
Motion System ◽  
Weigh In Motion ◽  
Comparative Accuracy ◽  
Bridge Weigh In Motion ◽  
Rational Management ◽  
Truck Weight

Roads and bridges are designed to meet the transportation demands for traffic volume and loading. Knowledge of the actual traffic is needed for a rational management of highway infrastructure. There are various procedures and equipment for measuring truck weight, including static and in weigh-in-motion techniques. This paper aims to compare four systems: portable scale, stationary truck weigh station, pavement weigh-in-motion system (WIM), and bridge weigh-in-motion system (B-WIM). The first two are reliable, but they have limitations as they can measure only a small fraction of the highway traffic. Weigh-in-motion (WIM) measurements allow for a continuous recording of vehicles. The presented study database was obtained at a location that allowed for recording the same traffic using all four measurement systems. For individual vehicles captured on a portable scale, the results were directly compared with the three other systems’ measurements. The conclusion is that all four systems produce the results that are within the required and expected accuracy. The recommendation for an application depends on other constraints such as continuous measurement, installation and operation costs, and traffic obstruction.

UAS measurements for the investigation of emissions of air pollutants at the Duesseldorf airport and industrial sites in the Rhine-Ruhr area, Germany

2021 ◽  
Author(s):  
Konradin Weber ◽  
Christian Fischer ◽  
Martin Lange ◽  
Tobias Pohl ◽  
Tim Kramer ◽  
...  
Keyword(s):  
Data Transmission ◽  
Air Pollutants ◽  
High Reliability ◽  
Measurement Techniques ◽  
Transmission System ◽  
Online Data ◽  
Ruhr Area ◽  
Measurement Systems ◽  
Industrial Sites ◽  
Data Transmission System

<p>Instrumented UAS (unmanned aerial systems, drones) can substantially enhance the capabilities for the investigation of air pollutants, when equipped with the appropriate and customized air pollution measurement systems. Important advantages can be found in the exploration of vertical and horizontal pollutant profiles as well as in the determination of fugitive emissions. The HSD Laboratory for Environmental Measurement Techniques (UMT) has developed a series of different multicopter UAS for various measurement tasks and payloads. Additionally, different commercial UAS are used by UMT. The multicopter UAS are equipped, depending on the measurement task, with different specifically adopted lightweight measurement systems for aerosols (PM10, PM2.5, PM1, UFP, PNC, number size distributions) or gases like O<sub>3</sub>, SO<sub>2</sub>, NO<sub>X</sub>, CO<sub>2</sub> and VOCs. All measurement systems were intercompared with certified standard measurement equipment before use to assure the quality of the measurement results. Moreover, physical samples of aerosols can be taken during the flight, which enables a chemical or REM analysis after the flight.</p><p>Additionally, UMT developed an on-line data transmission system, which allows the transmission of measurement data during the flights from the UAS to the ground for continuous monitoring. In this way concentration plumes can be tracked and hotspots can be pinpointed during the flight. This online data transmission system is independent of commercial platforms, can work on different radio frequencies in a push mode (presently on 2.4 GHz) and communicates with RS232 and I<sup>2</sup>C interfaces. Within several intercomparison studies this online data transmission proved a high reliability and correctness of transmitted data.</p><p>In addition to technical details of the UAS and instrumentation we present in this contribution the results of different measurement campaigns based on our UAS measurements:</p><ul><li>Investigations of emissions from the Duesseldorf airport combining upwind and downwind UAS measurements. These investigations became of special interest, as due to the reduced air traffic caused by the Corona pandemia now single aircraft starts and landings could be monitored with their emissions at elevated altitudes.</li> <li>Investigations of vertical concentration profiles above the city of Duesseldorf, which could be influenced by industrial sites in the north of Duesseldorf as well as by the Duesseldorf airport.</li> <li>Investigations of vertical and horizontal pollution distributions near, at and around industrial sites in the Rhine Ruhr area, especially of metal industry plants and chemical plants.</li> </ul><p>These examples highlight the capabilities of UAS measurements, which will be further enhanced by planned simultaneous use of several UAS in parallel and joint tasks.</p>

Total and fractional bedload transport in alpine streams approximated by different surrogate measurement systems

2021 ◽  
Author(s):  
Lorenz Ammann ◽  
Tobias Nicollier ◽  
Alexandre Badoux ◽  
Dieter Rickenmann
Keyword(s):  
Grain Size ◽  
Measurement Techniques ◽  
Bedload Transport ◽  
Accelerometer Sensor ◽  
Protection Measures ◽  
Measurement Systems ◽  
Size Classes ◽  
Alpine Streams ◽  
Surrogate Measurement ◽  
Using Data

<p>Knowledge about bedload transport in rivers is of high importance for many hydraulic engineering applications, in particular related to flood protection measures. Passive acoustic surrogate measurement techniques provide useful continuous estimates of bedload transport in terms of total mass, as well as for different grain-size classes.</p><p>We compare different surrogate measurement systems regarding their performance in quantifying total and fractional bedload transport in three alpine streams. The investigated measurement systems are the well-established Swiss plate geophone (SPG), an equivalent system in which the geophone sensor is replaced by an accelerometer sensor, and the miniplate accelerometer (MPA) system. The latter is a more recent device and consists of four small square metal plates embedded in elastomere elements. While the signal recorded with the SPG is known to be proportional to the transported bedload mass, we find that the MPA-signal shows a non-linear dependency. In addition, the MPA reacts more sensitively to small grain size classes than the other two systems, indicating a possible alternative to improve the quantification of bedload transport consisting of those classes.</p><p>Based on the raw signal recorded with the SPG and the MPA in a flume experiment, we test the ability of different empirical models to predict the known weight of the impacting particle. We show that it is possible to identify the particle weight with high accuracy with relatively simple models using data of either of the two measurement systems. One remaining challenge is to account for the site-to-site variability in the (amount of) signal caused by the combination of differing numbers of plates in the measurement setup and the lateral transmission of the signal across multiple plates, especially for the SPG system.</p>

Performance Prediction Hoftware for IACC Yachts

1993 ◽  
Author(s):  
Eric C. Schlageter ◽  
James R. Teeters
Keyword(s):  
Performance Prediction ◽  
Linear Optimization ◽  
Viscous Drag ◽  
Development Effort ◽  
Added Resistance ◽  
Induced Drag ◽  
Software Development Effort ◽  
Tank Test ◽  
America’S Cup ◽  
Wetted Area

The performance prediction software development effort undertaken by the Partnership for America's Cup Technology (PACT) is reviewed. First, PACT's origin, members, and mandate is covered, interspersed with a historical perspective of prediction software. Next, the new IACC rule with constraints is given. The hydrodynamic model format used in the software is described. Based on PACT tank test data, improved formulations for viscous drag, utilizing dynamic wetted area and length for canoe body drag and a 'stripping' method for appendage drag are presented. Corrections for Froude number and heel effects on induced drag are summarized. A new upwind sail model and added resistance model are discussed. The use of a race modeling program is illustrated with results from three separate design studies: a geosim family, a length scaling family, and an appendage study. Typical upright resistance, drag polar plots, lift plots, sea spectra, and added resistance data are presented. The final section describes current developments including speed enhancements, improved portability, and use of a multi-variable, non-linear optimization scheme to search the design space.

Before the Mining Begins

2010 ◽  
pp. 1-20
Author(s):  
Dries Verlet ◽  
Carl Devos
Keyword(s):  
Data Mining ◽  
Public Sector ◽  
Policy Evaluation ◽  
Reliable Data ◽  
Solid Base ◽  
Evidence Based ◽  
Negative Effects ◽  
The Public ◽  
Measurement Systems ◽  
The Right

Although policy evaluation has always been important, today there is a rising attention for policy evaluation in the public sector. In order to provide a solid base for the so-called evidence-based policy, valid en reliable data are needed to depict the performance of organisations within the public sector. Without a solid empirical base, one needs to be very careful with data mining in the public sector. When measuring performance, several unintended and negative effects can occur. In this chapter, the authors focus on a few common pitfalls that occur when measuring performance in the public sector. They also discuss possible strategies to prevent them by setting up and adjusting the right measurement systems for performance in the public sector. Data mining is about knowledge discovery. The question is: what do we want to know? What are the consequences of asking that question?

Full-Scale Linear Cutting Tests to Propose Some Empirical Formulas for TBM Disc Cutter Performance Prediction

2019 ◽  
Vol 52 (11) ◽  
pp. 4763-4783 ◽  
Author(s):  
Yucong Pan ◽  
Quansheng Liu ◽  
Xingxin Peng ◽  
Qi Liu ◽  
Jianping Liu ◽  
...  
Keyword(s):  
Performance Prediction ◽  
Full Scale ◽  
Disc Cutter ◽  
Empirical Formulas

Numerical Analysis of Weld Residual Stress in a Pressurizer Surge Nozzle Full-Scale Mockup: The Effect of Hardening Constitutive Model and Interpass Temperature

2015 ◽  
Author(s):  
Minh N. Tran ◽  
Ondrej Muránsky ◽  
Michael R. Hill ◽  
Mitchell D. Olson
Keyword(s):  
Thermal Analysis ◽  
Residual Stress ◽  
Kinematic Hardening ◽  
Measurement Techniques ◽  
Mechanical Analysis ◽  
Full Scale ◽  
Contour Method ◽  
Cooperative Research ◽  
Weld Residual Stress ◽  
Interpass Temperature

In an effort to shed light on accuracy and reliability of finite element (FE) weld modeling outputs, the U.S. Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) have been engaged in a program of cooperative research on weld residual stress (WRS) prediction. The current work presents numerical FE simulation of the WRS in a pressurizer surge nozzle full-scale mockup (Phase 2b), as a part of the broader NRC/EPRI program. Sequentially-coupled, thermo-mechanical FE analysis was performed, whereby the numerical solution from the thermal analysis was used as an input in the mechanical analysis. The thermal analysis made use of a dedicated weld modeling tool to accurately calibrate an ellipsoidal Gaussian volumetric heat source. The subsequent mechanical analysis utilized the isotropic and nonlinear kinematic hardening constitutive models to capture cyclic response of the material upon welding. The modeling results were then validated using a number of measurement techniques (deep hole drilling, contour method, slitting, and biaxial mapping). In addition, an effect of the interpass temperature (i.e. 24.5 °C, 150 °C, and 260 °C) on the final prediction of WRS is discussed.

The Two-Microphone Sound Intensity Probe

1988 ◽  
Vol 110 (1) ◽  
pp. 97-103 ◽  
Author(s):  
J. Pope
Keyword(s):  
Acoustic Field ◽  
Energy Flow ◽  
Average Rate ◽  
Measurement Techniques ◽  
Practical Interest ◽  
Sound Intensity ◽  
Pressure Sensing ◽  
Measurement Systems ◽  
Intensity Measurements ◽  
Validation Of Results

A probe consisting of a pair of pressure-sensing microphones is an integral part of most commonly used sound intensity measurement systems. Sound intensity is a vector that describes the average rate and direction of energy flow in an acoustic field. Recently the measurement of sound intensity has been of increasing theoretical and practical interest. The theory and technology of two-microphone probes are reviewed, with particular attention to the factors that impact the accuracy of intensity measurements. Proper measurement techniques and validation of results are discussed.

An Experimental and Numerical Investigation of the Effect of Axial Thermal Gradients in Flexible Pipes

2017 ◽  
Author(s):  
Dag Fergestad ◽  
Frank Klæbo ◽  
Jan Muren ◽  
Pål Hylland ◽  
Tom Are Grøv ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Section ◽  
Measurement Techniques ◽  
Full Scale ◽  
Model Complexity ◽  
Flexible Pipe ◽  
Element Analysis ◽  
Flexible Pipes ◽  
Full Scale Testing

This paper discusses the structural challenges associated with high axial temperature gradients and the corresponding internal cross section forces. A representative flexible pipe section designed for high operational temperature has been subject to full scale testing with temperature profiles obtained by external heating and cooling. The test is providing detailed insight in onset and magnitude of relative layer movements and layer forces. As part of the full-scale testing, novel methods for temperature gradient testing of unbonded flexible pipes have been developed, along with layer force- and deflection-measurement techniques. The full-scale test set-up has been subject to numerous temperature cycles of various magnitudes, gradients, absolute temperatures, as well as tension cycling to investigate possible couplings to dynamics. Extensive use of finite element analysis has efficiently supported test planning, instrumentation and execution, as well as enabling increased understanding of the structural interaction within the unbonded flexible pipe cross section. When exploiting the problem by finite element analysis, key inputs will be correct material models for the polymeric layers, and as-built dimensions/thicknesses. Finding the balance between reasonable simplification and model complexity is also a challenge, where access to high quality full-scale tests and dissected pipes coming back from operation provides good support for these decisions. Considering the extensive full scale testing, supported by advanced finite element analysis, it is evident that increased attention will be needed to document reliable operation in the most demanding high temperature flexible pipe applications.

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