scholarly journals Methods of Determination of Frictional Resistance for Prediction of Total Resistance of Inland Waterway Vessels

2018 ◽  
Vol 25 (s1) ◽  
pp. 68-73
Author(s):  
Jan Kulczyk
Keyword(s):  
Form Factor ◽  
Model Test ◽  
Water Depth ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Total Resistance ◽  
Inland Waterway ◽  
Correlation Line ◽  
Limited Depth

Abstract In the present paper presented are the results of prediction of total resistance of inland waterway vessels based on model test data. In scaling the resistance from model to full scale the extrapolation with two-dimensional frictional resistance formulation (without form factor) was applied, combined with different methods of determination of frictional (viscous) resistance coefficient. There were used the equations that include the effect of water depth, with and without account for pressure gradient. It was shown that limited depth of water substantially affects the frictional resistance. The results of example calculations are compared to resistance prediction made using the ITTC 1957 model-ship correlation line. Example calculations take into account the limited depth of water. Depending on the applied method of determination of frictional resistance coefficient the resultant total resistance of inland waterway vessel is higher or lower than the resistance based on the ITTC 1957 correlation line. The effect of water depth depends on the ratio of water depth to ship draught (h/T), on ship speed, and on the composition of a convoy. The extrapolation of resistance was made without including the form factor. Computations are made based on model test data for an inland waterway cargo vessel, for a kombi-type convoy of an inland waterway cargo vessel and a dumb barge, and for a convoy of two dumb barges without a pushboat.

DETERMINATION OF HEAD LOSSES IN PIPE-LINES LOSSES DURING HYDRAULIC CALCULATIONS FOR RINGED WATER NET

2012 ◽  
Vol 2 (2) ◽  
pp. 54-58
Author(s):  
E. M GAL'PERIN ◽  
A. L LUKS ◽  
E. A KRESTIN
Keyword(s):  
Comparative Analysis ◽  
Water Supply ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Head Losses ◽  
Tooth Surfaces ◽  
Experimental Researches ◽  
Frictional Resistance Coefficient ◽  
Pipe Lines

This paper provides the results of theoretical and experimental researches of head losses in industrial pipelines, which have technical coarseness. In the Nikuradzes researches values for frictional resistance coefficient were determined for artificial even-grained sandy roughness. The pipe-lines, which are used for water-supply in practice, have natural technical coarseness. The coarseness has different structure: it can have corrugated or saw-tooth surfaces and there can be also protective coat.The comparative analysis is provided for different methods of hydraulic losses calculations for head losses in pipe-lines for ringed water net. Recommendations for usage are also presented.

Resistance Characteristics of Fishing Boats Series of ITU

2008 ◽  
Vol 45 (04) ◽  
pp. 194-210
Author(s):  
Muhsin Aydin ◽  
Aydin Salci
Keyword(s):  
Form Factor ◽  
Scale Effects ◽  
Resistance Coefficient ◽  
The Black Sea ◽  
Viscous Resistance ◽  
Marmara Sea ◽  
Total Resistance ◽  
Hull Forms ◽  
Resistance Form ◽  
Resistance Tests

This paper presents the results of the resistance and propulsion tests carried out during the development of the Fishing Boat Hull Form Series of ITU, providing the means of designing modern fishing boats capable of operating in the Black Sea, Marmara Sea, Aegean Sea, and the Mediterranean Sea. Initially, nine modern hull forms were generated using the hull forms of the traditional Turkish fishing boats. The model resistance tests of these fishing boats were carried out in the lightship, loaded, and highly loaded conditions. In the present paper, these hull forms are introduced, followed by a systematic presentation of comparative results illustrating the scale effects and the extrapolation diagrams, the influence of the block coefficient, the length to beam ratio, the type of stern, the shape of chine and the fore and aft trim on viscous resistance (form factor k), and wave-making resistance (wave-making resistance coefficient CW). The findings on the effects of some appendages such as the rudder, the heel of the rudder and the stern tube on the viscous resistance (form factor k), and the total resistance (total resistance coefficient CTs) are also illustrated. Finally, a general discussion of the results obtained from the resistance tests, wake measurement tests, and flow visualization tests are presented.

scholarly journals Hull Form Factor Prediction of Mini Submarine Model Using Prohaska Method

2021 ◽  
Vol 3 (2) ◽  
pp. 160-164
Author(s):  
Mahendra Indiaryanto ◽  
Ahmad Syafi'ul Mujahid ◽  
Taufiq A Setyanto ◽  
Navik Puryantini
Keyword(s):  
Form Factor ◽  
Sea Level ◽  
Model Test ◽  
Water Depth ◽  
Ship Hull ◽  
Hull Form ◽  
Surface Ship ◽  
Surface Vessels ◽  
The Difference ◽  
Factor Coefficient

Speaking of prisoners on mini-submarines is certainly different Fnom the type of surface vessels in general. This is related to differences in the shape of the sub's hull when compared to surface ship. In addition to differences in the shape of the hull, the difference in the operational area of ​​the ship is also different, where the submarine's hull operates at full water depth, while the surface ship the ship hull partly operates at sea level. If the submarine model is tested then the value of the coefficient of resistance will be very different. Where the component of the coefficient of resistance (CT) consists of the coefficient of Fniction (CF), form factor (1+K), and Correlate Allowance (CA). Because the hull shape is different Fnom the surface ship, then the hull form factor coefficient is the focus of this study. The prediction of the hull form factor can be searched using the PROHASKA method. Where this method is done using a mini-submarine model test. By the known value of the hull form factor, then it can be used to find the value of the coefficient of resistance and can know the resistance of the ship

scholarly journals Numerical Calculation of the Tee Local Resistance Coefficient

2015 ◽  
Vol 9 (1) ◽  
pp. 876-881 ◽  
Author(s):  
Qin Zhang ◽  
Manlai Zhang ◽  
Zhihong Zhou ◽  
Shizhong Wei
Keyword(s):  
Cfd Simulation ◽  
Flux Ratio ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Head Loss ◽  
Local Resistance ◽  
Local Resistance Coefficient ◽  
Tee Junction ◽  
Resistance Coefficients

The local head loss of tee could be calculated with the determination of local resistance coefficient by CFD simulation and test. Based on the mesh-independent feature identified, the flow field inner tee was numerically simulated by the standard k - ε turbulent model and SIMPLEC algorithms, which has revealed the mainstream was obliged to turn to the opposite side of tee junction, and a rise in pressure drop between upstream and downstream was caused as a result. Furthermore, the frictional resistance coefficient was calculated for eliminating the frictional head loss of model, which decreased from 0.0207 to 0.0133 when the inlet velocity increased from 1 m/s to 12 m/s. Additionally, the local resistance coefficients of tee at flow conditions were attained, and the quadratic polynomial between the local resistance coefficient and flux ratio was presented due to the influence of branch on mainstream. Through the test, the simulation result has been compared and the effectiveness of simulation has been verified.

Analysis ofH3andHe3Form Factors and the Determination of the Charge Form Factor of the Neutron

1963 ◽  
Vol 11 (8) ◽  
pp. 387-390 ◽  
Author(s):  
L. I. Schiff ◽  
H. Collard ◽  
R. Hofstadter ◽  
A. Johansson ◽  
M. R. Yearian
Keyword(s):  
Form Factor ◽  
Charge Form Factor ◽  
Charge Form

The Relationship Between Frictional Resistance and Roughness for Surfaces Smoothed by Sanding

2002 ◽  
Vol 124 (2) ◽  
pp. 492-499 ◽  
Author(s):  
Michael P. Schultz
Keyword(s):  
Reynolds Number ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Polished Surface ◽  
Average Height ◽  
Freestream Velocity ◽  
Number Range ◽  
Test Fixture ◽  
Plate Length ◽  
The Relationship

An experimental investigation has been carried out to document and relate the frictional resistance and roughness texture of painted surfaces smoothed by sanding. Hydrodynamic tests were carried out in a towing tank using a flat plate test fixture towed at a Reynolds number ReL range of 2.8×106−5.5×106 based on the plate length and freestream velocity. Results indicate an increase in frictional resistance coefficient CF of up to 7.3% for an unsanded, as-sprayed paint surface compared to a sanded, polished surface. Significant increases in CF were also noted on surfaces sanded with sandpaper as fine as 600-grit as compared to the polished surface. The results show that, for the present surfaces, the centerline average height Ra is sufficient to explain a large majority of the variance in the roughness function ΔU+ in this Reynolds number range.

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