Full Scale Thruster-Hull Interaction Improvement Revealed With CFD Analysis

2013 ◽  
Author(s):  
Norbert Bulten ◽  
Petra Stoltenkamp
Keyword(s):  
Open Water ◽  
Full Scale ◽  
Full Potential ◽  
Cfd Analysis ◽  
Calculation Methods ◽  
Pronounced Difference ◽  
Shaft Line ◽  
Comparable Performance ◽  
Improved Performance ◽  
Open Water Performance

The performance of two steerable thruster configurations has been compared: a more conventional straight unit and a tilted-shaft-line unit. Based on a theoretical approach, it has been shown that the full scale bollard pull performance of both units is close to the realistic optimum. The open water performance of the units revealed comparable performance at bollard pull for the straight and tilted unit. A more pronounced difference in favor of the straight unit is found in free sailing condition. When the thruster-hull interaction effects are taken into account, the trends change however. Some typical cases have been analyzed in detail with RANS-CFD numerical analysis methods: a drill ship in free sailing and bollard pull condition and a drill rig in bollard pull condition. The thrust-deduction factors are reduced significantly for all analyzed cases when the tilted unit is compared to the straight unit. This leads to improved performance of the complete vessel. In order to capture the full potential of the tilted-shaft line thruster units, a detailed review of the currently used DP-capability calculation methods needs to be made. Besides the reduced thrust-deduction factors due to hull interaction, also the forbidden-zones due to thruster-thruster interaction need to be reviewed. The downward deflection of the jet in case of tilted units will reduce the zones of interaction with other thrusters. Based on the currently presented research, it should be clear that the tilted thruster concept has a large potential for drill ships and drill rigs. A very good DP-capability will be achieved with the currently installed powers.

An Investigation Into the Effect of Biofouling on Full-Scale Propeller Performance Using CFD

2019 ◽  
Author(s):  
Soonseok Song ◽  
Yigit Kemal Demirel ◽  
Mehmet Atlar
Keyword(s):  
Open Water ◽  
Full Scale ◽  
Roughness Effect ◽  
Thrust Coefficient ◽  
Propulsion Performance ◽  
Negative Effect ◽  
Precise Prediction ◽  
Torque Coefficient ◽  
Open Water Performance ◽  
Propeller Performance

Abstract The negative effect of biofouling on ship resistance has been investigated since the early days of naval architecture. However, for more precise prediction of fuel consumption of ships, understanding the effect of biofouling on ship propulsion performance is also important. In this study, CFD simulations for the full-scale performance of KP505 propeller in open water, including the presence of marine biofouling, were conducted. To predict the effect of barnacle fouling on the propeller performance, experimentally obtained roughness functions of barnacle fouling were employed in the wall-function of the CFD software. The roughness effect of barnacles of varying sizes and coverages on the propeller open water performance was predicted for advance coefficients ranging from 0.2 to 0.8. From the simulations, drastic effects of barnacle fouling on the propeller open water performance were found. The result suggests that the thrust coefficient decreases while the torque coefficient increases with increasing level of surface fouling, which leads to a reduction of the open water efficiency of the propeller. Further investigations into the roughness effect on the pressure and velocity field, surface pressure and wall shear stress, and propeller vortices were examined.

Computational and experimental studies of the strength of full-scale samples of pipes with defects "metal loss" and "dent with groove"

2020 ◽  
Vol 10 (3) ◽  
pp. 226-233
Author(s):  
Dmitry A. Neganov ◽  
◽  
Victor M. Varshitsky ◽  
Andrey A. Belkin ◽  
◽  
...  
Keyword(s):  
Internal Pressure ◽  
Experimental Studies ◽  
Full Scale ◽  
The Other ◽  
Metal Loss ◽  
Calculation Methods ◽  
Reliable Operation ◽  
Sufficient Stability ◽  
Comparative Results ◽  
The Moment

The article contains the comparative results of the experimental and calculated research of the strength of a pipeline with such defects as “metal loss” and “dent with groove”. Two coils with diameter of 820 mm and the thickness of 9 mm of 19G steel were used for full-scale pipe sample production. One of the coils was intentionally damaged by machining, which resulted in “metal loss” defect, the other one was dented (by press machine) and got groove mark (by chisel). The testing of pipe samples was performed by applying static internal pressure to the moment of collapse. The calculation of deterioration pressure was carried out with the use of national and foreign methodical approaches. The calculated values of collapsing pressure for the pipe with loss of metal mainly coincided with the calculation experiment results based on Russian method and ASME B31G. In case of pipe with dent and groove the calculated value of collapsing pressure demonstrated greater coincidence with Russian method and to a lesser extent with API 579/ASME FFS-1. In whole, all calculation methods demonstrate sufficient stability of results, which provides reliable operation of pipelines with defects.

Biotower Pilot Study Results for a Photographic and Specialty Paper Manufacturer

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2109-2112
Author(s):  
J. G. Cleary ◽  
T. J. Boehm ◽  
R. J. Geary
Keyword(s):  
New York ◽  
Pilot Study ◽  
New York State ◽  
Cross Flow ◽  
Full Scale ◽  
Treatment System ◽  
Salmon River ◽  
Study Results ◽  
Comparable Performance ◽  
Pollutant Discharge

Schoeller Technical Papers, Inc. (Schoeller), which manufactures photographic and other specialty papers, is located in Pulaski, New York. The wastewater treatment system consists of a primary clarifier and two settling lagoons. Secondary treatment using a biotower was proposed to meet the new New York State Pollutant Discharge Elimination System (SPDES) discharge limits for BOD and TSS. The effluent from each basin is discharged directly to the Salmon River, at an approximate average flow of 1.6 million gallons/day (mgd). A biotower pilot study was performed to evaluate the suitability of a biotower treatment process for treating the total effluent from Schoeller's facility. The pilot study was used to select the media for the full-scale biotower and to confirm the design loading for the full-scale biotower, which proceeded in parallel with the pilot study due to the schedule constraints. Two pilot systems were operated to compare a conventional cross-flow and vertical media. Test data were collected to evaluate the performance of each pilot treatment system at a range of loading conditions and to develop the design loading information for the full-scale plant. The pilot units were operated for a period of 10 months. BOD concentrations to the pilot units averaged 58 mg/l with a peak of 210 mg/l. Approximately 80% of the BOD was soluble. BOD loadings averaged 21 lb BOD/day/1,000 cubic feet with a peak of 77 lb BOD/day/1,000 cubic feet. Both pilot units achieved excellent BOD removals exceeding 75%, with average effluent soluble BOD concentration less than 10 mg/l and average effluent TSS concentrations of 12 mg/l. The two media achieved comparable performance throughout most of the pilot study.

Optimization of RANS Solver Simulation Setup for Propeller Open Water Performance Prediction

2015 ◽  
Author(s):  
Mohammed Islam ◽  
Fatima Jahra ◽  
Michael Doucet
Keyword(s):  
Domain Size ◽  
Open Water ◽  
Fractional Factorial ◽  
Navier Stokes ◽  
Calm Water ◽  
Simulation Results ◽  
Open Water Performance ◽  
Thrust And Torque ◽  
Simulation Time ◽  
Fixed Pitch

Mesh and domain optimization strategies for a RANS solver to accurately estimate the open water propulsive characteristics of fixed pitch propellers are proposed based on examining the effect of different mesh and computation domain parameters. The optimized mesh and domain size parameters were selected using Design of Experiments (DoE) methods enabling simulations to be carried out in a limited memory environment, and in a timely manner; without compromising the accuracy of results. A Reynolds-Averaged Navier Stokes solver is used to predict the propulsive performance of a fixed pitch propeller. The predicted thrust and torque for the propeller were compared to the corresponding measurements. A total of six meshing parameters were selected that could affect the computational results of propeller open water performance. A two-level fractional factorial design was used to screen out parameters that do not significantly contribute to explaining the dependent parameters: namely simulation time, propeller thrust and propeller torque. A total of 32 simulations were carried out only to find out that the selected six meshing parameters were significant in defining the response parameters. Optimum values of each of the input parameters were obtained for the DOE technique and additional simulations were run with those parameters. The simulation results were validated using open water experimental results of the same propeller. It was found that with the optimized meshing arrangement, the propeller opens simulation time was reduced by at least a factor of 6 as compared to the generally popular meshing arrangement. Also, the accuracy of propulsive characteristics was improved by up to 50% as compared to published simulation results. The methodologies presented in this paper can be similarly applied to other simulations such as calm water ship resistance, ship propulsion to systematically derive the optimized meshing arrangement for simulations with minimal simulation time and maximum accuracy. This investigation was carried out using STAR-CCM+, a commercial CFD package; however the findings can be applied to any RANS solver.

Preliminary Evaluation of the 24 Ft. Diameter Fan Performance In the MinWaterCSP Large Cooling Systems Test Facility

2021 ◽  
Author(s):  
S. J. van der Spuy ◽  
D. N. J. Els ◽  
L. Tieghi ◽  
G. Delibra ◽  
A. Corsini ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Static Pressure ◽  
Cooling System ◽  
Pressure Rise ◽  
Full Scale ◽  
Test Facility ◽  
Small Scale ◽  
Preliminary Evaluation ◽  
Cfd Analysis ◽  
Setting Angle

Abstract The MinWaterCSP project was defined with the aim of reducing the cooling system water consumption and auxiliary power consumption of concentrating solar power (CSP) plants. A full-scale, 24 ft (7.315 m) diameter model of the M-fan was subsequently installed in the Min WaterCSP cooling system test facility, located at Stellenbosch University. The test facility was equipped with an in-line torque arm and speed transducer to measure the power transferred to the fan rotor, as well as a set of rotating vane anemometers upstream of the fan rotor to measure the air volume flow rate passing through the fan. The measured results were compared to those obtained on the 1.542 m diameter ISO 5801 test facility using the fan scaling laws. The comparison showed that the fan power values correlated within +/− 7% to those of the small-scale fan, but at a 1° higher blade setting angle for the full-scale fan. To correlate the expected fan static pressure rise, a CFD analysis of the 24 ft (7.315 m) diameter fan installation was performed. The predicted fan static pressure rise values from the CFD analysis were compared to those measured on the 1.542 m ISO test facility, for the same fan. The simulation made use of an actuator disc model to represent the effect of the fan. The results showed that the predicted results for fan static pressure rise of the installed 24 ft (7.315 m) diameter fan correlated closely (smaller than 1% difference) to those of the 1.542 m diameter fan at its design flowrate but, once again, at approximately 1° higher blade setting angle.

scholarly journals Gaming the Performance: Massively Multiplayer Online Games and Performance Outcomes in English and Business Courses

2018 ◽  
Vol 11 (2) ◽  
Author(s):  
Papia Bawa ◽  
Sunnie Lee Watson ◽  
William Watson
Keyword(s):  
Technology Integration ◽  
Online Games ◽  
Performance Outcomes ◽  
Instructional Designers ◽  
Full Potential ◽  
Massively Multiplayer Online Games ◽  
Business Courses ◽  
Multiplayer Online Games ◽  
Improved Performance ◽  
Massively Multiplayer

The push for technology integration in classrooms calls for examinations of available options, particularly those that have not yet been used to their full potential for various reasons. One such technology is digital commercial games which, though designed for entertainment, may have potential educational benefits. Although there have been several discussions in the literature about the possibilities of such commercial video games as educational assets, there persists a gap in our understanding of the value of such games in the context of Higher Education. This gap is particularly visible when it comes to studies on how commercial games may affect performance outcomes in multiple disciplines. Thus, this study examined Massively Multiplayer Online Games (MMOGs), one genre of commercial games, in two disciplines, to discover how, and if, they improved learner performances. This information could help facilitate technology integration in new and interesting ways for institutions, instructors, and instructional designers. Using a True Experimental design that examined the performance scores of 214 students in English and Business courses, the effect of using MMOGs on participation scores was analyzed from multiple statistical perspectives. The findings strongly suggest that using MMOGs helped experimental groups to perform better. Additionally, there are strong indications that game related content like game wikis, blogs, game site information, and game video tutorials was also instrumental in improved performance, irrespective of active gameplay or not. This is significant as it may provide easier-to-integrate options for MMOGs in the curriculum. Practitioner, theoretical and research implications are also discussed.

Oil Skimming Efficiency of the SOS: Scaling From GeoSim Model Tests to Full Scale Prototype Operations

2012 ◽  
Author(s):  
Günther F. Clauss ◽  
Sascha Kosleck ◽  
Florian Sprenger ◽  
Laura Grüter
Keyword(s):  
Flow Pattern ◽  
Oil Recovery ◽  
Open Water ◽  
Model Tests ◽  
Full Scale ◽  
Polluted Water ◽  
Water Separation ◽  
Weathering Processes ◽  
River Elbe ◽  
Hydrodynamic Effects

The severe ecological and economical aftermath of the 2010 ‘Deepwater Horizon’ catastrophe in the Gulf of Mexico clearly shows the insufficiency of current oil recovery systems which cannot operate in wave heights above 1.5m. To prevent emulsification and weathering processes, it is necessary to skim the oil film off the sea surface shortly after the accident. The autonomous SOS (Sea State-independent Oil Skimming System) developed within the framework of the research project SOS3 features high transit velocities, the capability of operating in rough seas and a massive intake of oil polluted water — and is therefore a unique technology. The oil water separation process of the SOS is purely based on hydrodynamic principles involving vortex evolution and a special flow pattern inside the internal moon pool. These requirements for efficient oil skimming operations depend on various hydrodynamic effects that would imply model testing in compliance with Froude’s and Reynolds’ law simultaneously — a physically impossible condition. Therefore GeoSim model tests with the SOS at model scales of 1:16, 1:25 and 1:36 are conducted with discrete particles of the correct density substituting the oil phase. The tendencies in flow pattern evolution and oil skimming efficiency are compared and extrapolated to full scale. Results from open water tests with the prototype of the SOS in the mouth of river Elbe serve for validation of the extrapolated results.

A change in granularity: measure space utilization through smart technologies

Facilities ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chiara Tagliaro ◽  
Yaoyi Zhou ◽  
Ying Hua
Keyword(s):  
Smart Sensors ◽  
Full Potential ◽  
Calculation Methods ◽  
Space Utilization ◽  
Data Set ◽  
Content Type ◽  
Office Space ◽  
Challenges And Opportunities ◽  
Utilization Data ◽  
Smart Technologies

Purpose Workplace space utilization data reveals patterns of space usage, the occupants’ presence and mobility within the office building. Nowadays, emerging technology such as smart sensors and devices can revolutionize the measurement of space utilization data, which is originally dominated by human observers with paper and pencil. However, these novel instruments are often used in an old fashion, which restricts the exploitation of their full potential. This study aims to shed new light on the benefits and limits of using smart technology in measuring space utilization data and discusses the challenges and opportunities in analyzing the data measured by smart sensors. Design/methodology/approach First, the literature regarding common methods and previous studies about office space utilization measurement was reviewed. Then, a data set consisting of space utilization data collected through Passive Infra-Red sensors for 35 meeting rooms in a bank building was carefully evaluated. Finally, the space utilization results based on methods calculated in two different granularities were compared. Findings The number of occupied hours calculated at an hour level was 1.32-hour larger than that calculated at a minute level. As both results show the concept of space utilization, which was the amount of time that the space was occupied, this paper revealed a gap between the two space utilization calculation methods and further discussed the issues and challenges for future space utilization data analysis and benchmarking. Originality/value To the best of the authors’ knowledge, this is the first study critically addressing office space utilization issues by comparing calculation methods in different granularity.

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