scholarly journals An analytical model for vortex at vertical intakes

2021 ◽  
Author(s):  
Hamed Sarkardeh ◽  
Morteza Marosi
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Vortex Formation ◽  
Surface Profile ◽  
Pressure Distributions ◽  
Free Surface Vortex ◽  
Spiral Form ◽  
Solution Velocity ◽  
Good Agreement ◽  
Surface Vortex

Abstract In the present paper, free surface vortex formation at intakes is investigated analytically. By assuming a spiral form for vortex streamlines, continuity and momentum equations were integrated and solved in a vortex flow domain. From this solution, velocity and pressure distributions were found above the intake under vortex action. An equation for the water surface profile was also found and compared with another research. By considering that in an air core vortex, pressure at the intake entrance drops to zero, a relationship was found for critical submerged depth and verified by experimental data and another analytical equation. It was concluded that the results of the proposed spiral analytical model had good agreement with the experimental data.

scholarly journals Response of a Warped Flexible Rotor with a Fluid Bearing

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Jim Meagher ◽  
Xi Wu ◽  
Chris Lencioni
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Equation Of Motion ◽  
Diagnostic Information ◽  
Flexible Rotor ◽  
Vibration Data ◽  
Rotor Model ◽  
Good Agreement

A two-complex-degrees-of-freedom model is developed and compared to experimental data for various amounts of rotor bow and its orientation to mass imbalance of the rotor. The equation of motion is developed by adding constant forces that rotate with the rotor to a Bently-Muszynska two-mode isotropic rotor model with a plane journal bearing. Diagnostic information discernable from probes at the bearing is explored and compared to midspan response, where previous research has concentrated. The model presented also extends earlier work by representing the effect of a nonrigid bearing. Good agreement between the analytical model and experiment demonstrates that the analysis presented can be useful to diagnose and balance residual shaft bow from probes located at the bearings, where vibration data are typically more available than midspan probes.

scholarly journals Numerical Simulation of Rotor in Hover and Forward Flight

2018 ◽  
Vol 179 ◽  
pp. 03011
Author(s):  
Qinghe Zhao
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Moving Grid ◽  
Steady State Flow ◽  
Forward Flight ◽  
Numerical Simulation Result ◽  
Structured Grid ◽  
Pressure Distributions ◽  
Good Agreement

The flow around rotor is numerical simulated in hover and forward flight based on multi-structured grid. In hover the flow field can be transformed into a steady-state flow field in the rotating coordinate system. The experimental data of Caradonna and Tung rotor is used to verify the numerical simulation result. The numerical results compare well with the experimental data for both non-lifting and lifting cases. Non-lifting forward flight is simulated and the prediction capabilities have been validated through the ONERA two-blade rotor. The pressure distributions of different positions under different azimuth angles are compared, which is in good agreement with the experimental data. There is unsteady shock wave when forward flight. Dual-time method is used to obtain unsteady flow field with rigid moving grid in the inertial system.

A Simple Analytical Model to Simulate Oblique Ballistic Impact onto Fabric

2011 ◽  
Vol 110-116 ◽  
pp. 3453-3458
Author(s):  
Mohamad Ali Akbari ◽  
Golam Hosein Liaghat ◽  
Hadi Sabouri
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Ballistic Impact ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Good Agreement

A simple analytical model for oblique ballistic impact of projectiles into fabrics are presented. This model is extension of Chocron-Benloulo penetration model. Results are compared with experimental data. There is good agreement between analytical and experimental results.

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

Dynamics Analytical Model of Cutting Force in Metal Cutting Processing

2011 ◽  
Vol 308-310 ◽  
pp. 1211-1214
Author(s):  
Jian Ying Guo ◽  
Wen Bin Li ◽  
Shi Ying Wang ◽  
Ming Lv
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Analytical Model ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Static Balance ◽  
Impact Effect ◽  
New Formula ◽  
Suggested Formula ◽  
Good Agreement

Cutting force is an important parameter in machining. The static balance method and experience formulas had been adopted to find its value, but the theoretical calculated value is not good agreement with the experimental value for the same set of cutting conditions. In practical machining, the cutting tool has obvious impact effect on workpiece, so a dynamics analytical model for cutting process is established in this paper. Based on the proposed solution, a new formula for cutting force has been obtained. The suggested formula has shown to correspond well with the experimental data.

scholarly journals Mechanism Analysis of Free-Surface Vortex Formation during Steel Teeming

2014 ◽  
Vol 54 (7) ◽  
pp. 1592-1600 ◽  
Author(s):  
Hong-Xia Li ◽  
Qiang Wang ◽  
Hong Lei ◽  
Jia-Wei Jiang ◽  
Zhan-Cheng Guo ◽  
...  
Keyword(s):  
Free Surface ◽  
Vortex Formation ◽  
Mechanism Analysis ◽  
Free Surface Vortex ◽  
Surface Vortex

Nonlinear stress analysis of muskeg via finite element

1991 ◽  
Vol 28 (4) ◽  
pp. 613-629 ◽  
Author(s):  
R. N. Yong ◽  
A. M. O. Mohamed ◽  
R. G. Tali
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Key Words ◽  
Analytical Model ◽  
Constitutive Behavior ◽  
Experimental Program ◽  
Nonlinear Stress ◽  
Stress And Deformation ◽  
Element Technique ◽  
Good Agreement

The purpose of this paper is to provide a rational analytical means for predicting the performance of a muskeg deposit under loading. The analytical model employs the finite-element technique, which is extended to take into consideration the unusual constitutive behavior of the fibrous organic materials as well as the tension cut developing in these materials. The solution obtained using this model provides detailed stress and deformation fields within the loaded muskeg deposit. The applicability of the proposed analytical model is verified by conducting an appropriate experimental program. The results obtained from the model are found to be in good agreement with the experimental data. Key words: muskeg, loading, modelling, anisotropic, finite element, tension, compression.

scholarly journals Analytical model for electrohydrodynamic thrust

2020 ◽  
Vol 476 (2241) ◽  
pp. 20200220
Author(s):  
Ravi Sankar Vaddi ◽  
Yifei Guan ◽  
Alexander Mamishev ◽  
Igor Novosselov
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Momentum Transfer ◽  
Analytical Model ◽  
First Principles ◽  
Thrust Force ◽  
Propulsion Systems ◽  
One Dimensional ◽  
Charged Species ◽  
Good Agreement

Electrohydrodynamic (EHD) thrust is produced when ionized fluid is accelerated in an electric field due to the momentum transfer between the charged species and neutral molecules. We extend the previously reported analytical model that couples space charge, electric field and momentum transfer to derive thrust force in one-dimensional planar coordinates. The electric current density in the model can be expressed in the form of Mott–Gurney law. After the correction for the drag force, the EHD thrust model yields good agreement with the experimental data from several independent studies. The EHD thrust expression derived from the first principles can be used in the design of propulsion systems and can be readily implemented in the numerical simulations.

Sign in / Sign up

Export Citation Format

Share Document