Computation of High-Speed Turbulent Flow about a Ship Model with a Transom Stern.

1997 ◽  
Author(s):  
H. J. Haussling ◽  
R. W. Miller ◽  
R. M. Coleman
Keyword(s):  
Turbulent Flow ◽  
High Speed ◽  
Ship Model

Performance Analysis of High Speed Floating Ring Hybrid Bearing in the Laminar and Turbulent Regimes

2011 ◽  
Vol 197-198 ◽  
pp. 1776-1780 ◽  
Author(s):  
Hong Guo ◽  
Bo Qian Xia ◽  
Shao Qi Cen
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Flow Equation ◽  
The Finite Element Method ◽  
Static And Dynamic Characteristics ◽  
Hybrid Bearing

This paper presents a theoretical study concerning the static and dynamic characteristics of high speed journal floating ring hybrid bearing compensated by interior restrictor under laminar flow and turbulent flow respectively. The turbulent flow fluid film control equations and the pressure boundary conditions of this floating ring bearing together with the restrictor flow equation are solved by using the Finite Element Method. The variation regularity of static and dynamic characteristics such as load capacity, friction power loss, stiffness, damping etc. is analyzed. By comparing the laminar flow results and turbulent flow results, it is found that the characteristics coefficients are adjacent under small Reynolds number (laminar flow is dominant). But the characteristics coefficients are discrepant under big Reynolds number (turbulent flow is dominant). So turbulence lubrication theory is more accurate to high speed floating ring bearing.

Study on the Turbulent Injury Principle of Blood in the High-Speed Spiral Blood Pump

2011 ◽  
Vol 393-395 ◽  
pp. 992-995
Author(s):  
Zhong Yun ◽  
Chuang Xiang ◽  
Xiao Yan Tang ◽  
Fen Shi
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Blood Cell ◽  
Turbulent Flow ◽  
Red Blood Cell ◽  
Blood Cells ◽  
High Speed ◽  
Internal Flow ◽  
Blood Pump ◽  
Turbulent Flow Field

The strongly swirling turbulent flow in the internal flow field of a high-speed spiral blood pump(HSBP), is one of important factors leading to the fragmentation of the red blood cell(RBC) and the hemolysis. The study on the turbulent injure principle of blood in the HSBP is carried out by using the theory of waterpower rotated flow field and the hemorheology. The numerical equation of the strongly swirling turbulent flow field is proposed. The largest stable diameter of red blood cells in the turbulent flow field is analyzed. The determinant gist on the red blood cell turbulent fragmentation is obtained. The results indicate that in the HSMP, when turbulent flow is more powerful, shear stress is weaker, the vortex mass with energy in flow field may cause serious turbulent fragmentation because of the diameter which is smaller than the RBC’s. The RBC’s turbulent breakage will occur when the Weber value is larger than 12.

Study of a Container Ship with Breaking Waves at High Froude Number Using URANS and DDES Methods

2019 ◽  
Author(s):  
Jianhua Wang ◽  
Zhen Ren ◽  
Decheng Wan
Keyword(s):  
Free Surface ◽  
Wave Breaking ◽  
High Speed ◽  
Hydrodynamic Performance ◽  
Small Scale ◽  
Breaking Wave ◽  
Container Ship ◽  
Ship Model ◽  
Bow Waves ◽  
Bow Wave

The KRISO container ship model is used for numerical simulations to investigate hydrodynamic performance under high speeds. Unsteady Reynolds-Averaged Navier-Stokes (URANS) and delayed detached eddy simulation (DDES) approaches are used to resolve the flow field around the ship model. High-resolution Volume of Fluid (VOF) technique in OpenFOAM is used to capture the free surface. The present work focuses on the wave-breaking phenomena of high-speed ships. To study the speed effects on the phenomenon of ship bow wave breaking, three different speeds, i.e., Fn = .26, .35, and .40, are investigated for a fixed ship model in calm water. Predicted resistance and wave patterns under Fn = .26 are validated with available experimental data, and a good agreement is achieved. The breaking wave phenomena can be observed from both URANS and DDES results for Froude numbers greater than .35. And the Fn = .40 case shows more violent breaking bow waves. The process of overturning and breaking of bow wave is more complex in the DDES results, and some small-scale free surface features are also captured. The predicted bow wave is compared with the experiment conducted at the China Ship Scientific Research Center. It shows that the DDES results are more accurate. Wave profiles and vorticity field at several cross sections are presented to illustrate the relationship between bow waves and vortices. It is found that the free surface vorticity dissipates quickly in the URANS simulation, which leads to the difference compared with the DDES results.

scholarly journals Numerical Simulation of Turbulent Flow on a High-Speed Crossflow Blowing over Array Slots with Weak Injection

2015 ◽  
Vol 75 ◽  
pp. 1734-1739 ◽  
Author(s):  
Mei Lin ◽  
Xuefang Xu ◽  
Bo Wu ◽  
Liangbi Wang ◽  
Qiuwang Wang
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flow ◽  
High Speed

BLENDING CHARACTERISTICS OF HIGH-SPEED ROTARY IMPELLERS

2013 ◽  
Vol 34 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Ivan Fořt ◽  
Pavel Seichter ◽  
Luboš Pešl ◽  
František Rieger ◽  
Tomáš Jirout
Keyword(s):  
Turbulent Flow ◽  
Flow Regime ◽  
High Speed ◽  
Large Scale ◽  
Energy Savings ◽  
Axial Flow ◽  
Power Input ◽  
Maximum Energy ◽  
Cylindrical Vessel ◽  
Turbulent Flow Regime

Abstract This paper presents a comparison of the blending efficiency of eight high-speed rotary impellers in a fully baffled cylindrical vessel under the turbulent flow regime of agitated charge. Results of carried out experiments (blending time and impeller power input) confirm that the down pumping axial flow impellers exhibit better blending efficiency than the high-speed rotary impellers with prevailing radial discharge flow. It follows from presented results that, especially for large scale industrial realisations, the axial flow impellers with profiled blades bring maximum energy savings in comparison with the standard impellers with inclined flat blades (pitched blade impellers).

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