scholarly journals Added Mass and Damping of a Vibrating Rod in Confined Viscous Fluids

1976 ◽  
Vol 43 (2) ◽  
pp. 325-329 ◽  
Author(s):  
S. S. Chen ◽  
M. W. Wambsganss ◽  
J. A. Jendrzejczyk
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Cylindrical Shell ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Viscous Fluids ◽  
Series Of Experiments ◽  
Theoretical Results ◽  
Good Agreement

This paper presents an analytical and experimental study of a cylindrical rod vibrating in a viscous fluid enclosed by a rigid, concentric cylindrical shell. A closed-form solution for the added mass and damping coefficient is obtained and a series of experiments with cantilevered rods vibrating in various viscous fluids is performed. Experimental data and theoretical results are in good agreement.

Analysis on a Counter-Current Flow Hemodialyzer

2009 ◽  
Vol 4 (5) ◽  
Author(s):  
Norman W Loney
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Closed Form Solution ◽  
Maximum Error ◽  
Form Solution ◽  
Transfer Coefficients ◽  
Confluent Hypergeometric Functions ◽  
Proposed Model ◽  
Counter Current ◽  
Good Agreement

The closed form solution to the conjugated boundary value problem posed by a counter current hemodialyzer facilitates the estimation of the overall mass transfer coefficient. Comparison of the proposed model results with published experimental data shows good agreement for Urea and Creatinine clearances over a published range of blood and dialyzate flow rates. This model predicts clearances with a maximum error of less than 4% for both Urea and Creatinine when blood flow is 75% of the dialyzate flow. However, when both blood and dialyzate flows are identical the model over predicts the experimental data by 1.47% in the case of Urea and 4.75 for Creatinine flows of 300 ml/min. Although the concentration profile is an infinite series involving confluent hypergeometric functions, 2 terms of the series were sufficient (Mathematica notebook program) to produce these results. Overall mass transfer coefficients can now be deduced from the Sherwood numbers and provide possible improvement over currently used area coefficients.

Interaction Between Two Bodies Translating in an Inviscid Fluid

1991 ◽  
Vol 35 (01) ◽  
pp. 1-8
Author(s):  
L. Landweber ◽  
A. T. Chwang ◽  
Z. Guo
Keyword(s):  
Translational Motion ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Circular Cylinders ◽  
Integral Approach ◽  
Inviscid Fluid ◽  
Added Masses ◽  
Two Bodies ◽  
Good Agreement

The equations of motion of two bodies in translational motion in an inviscid fluid at rest at infinity are expressed in Lagrangian form. For the case of one body stationary and the other approaching it in a uniform stream, an exact, closed-form solution in terms of added masses is obtained, yielding simple expressions for the velocity of the moving body as a function of its relative position and for the interaction forces. This solution is applied to the case of a rectangular cylinder approaching a cylindrical one, for which the added-mass coefficients had been previously obtained in a companion paper by an integral-equation procedure. In order to compare results with those in the literature, and to evaluate the accuracy of the present procedures, results were calculated for a pair of circular cylinders by these methods as well as by successive images. Very good agreement was found. Comparison with published results showed good agreement with the added mass but very poor agreement on the forces, including disagreement as to whether the forces were repulsive or attractive. The discrepancy is believed to be due to the omission of terms in the Bernoulli equation which was used to obtain the pressure distribution and then the force on a body. The Lagrangian formulation is believed to be preferable to the pressure-integral approach because it yields the hydrodynamic force directly in terms of the added masses and their derivatives, thus requiring the calculation of many fewer coefficients.

Effect of Different Input Loading Form on Structure-Born Sound Radiation

2012 ◽  
Vol 518-523 ◽  
pp. 3768-3771
Author(s):  
Zhi Yong Xie ◽  
Qi Dou Zhou ◽  
Gang Ji
Keyword(s):  
Experimental Data ◽  
Forced Vibration ◽  
Sound Radiation ◽  
Added Mass ◽  
Elastic Vibration ◽  
Simulation And Experiment ◽  
Radiation Induced ◽  
Vibration And Sound Radiation ◽  
Loading Form ◽  
Good Agreement

The exciting force’s accurate measurement of is crucial to the structure-born sound radiation. Forced vibration and sound radiation of the ribbed cylinder is examined in the anechoic room. An approach called added mass and damping method is proposed to calculate the elastic vibration and acoustic field of the cylinder. Results obtained from simulation are show to be in good agreement with the experimental data. Sound radiation induced by different input loading form is examined via simulation and experiment. And the equipollence of force and pressure acting on the base is validated.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

Validation of Nitinol SMA Characteristics Using Finite Element Analysis and Closed Form Solutions

2013 ◽  
Vol 856 ◽  
pp. 147-152
Author(s):  
S.H. Adarsh ◽  
U.S. Mallikarjun
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fe Analysis ◽  
Element Analysis ◽  
Complex Behaviour ◽  
Closed Form Solutions

Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

DYNAMIC POWER DISSIPATION FORMULATION FOR APPLICATION IN DYNAMIC PROGRAMMING BUFFER INSERTION ALGORITHM

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Chessda Uttraphan ◽  
Nasir Shaikh-Husin ◽  
M. Khalil-Hani
Keyword(s):  
Dynamic Programming ◽  
Closed Form ◽  
Power Dissipation ◽  
Closed Form Solution ◽  
Propagation Delay ◽  
Form Solution ◽  
Buffer Insertion ◽  
Dynamic Power ◽  
Insertion Algorithm ◽  
Series Of Experiments

Buffer insertion is a very effective technique to reduce propagation delay in nano-metre VLSI interconnects. There are two techniques for buffer insertion which are: (1) closed-form solution and (2) dynamic programming. Buffer insertion algorithm using dynamic programming is more useful than the closed-form solution as it allows the use of multiple buffer types and it can be used in tree structured interconnects. As design dimension shrinks, more buffers are needed to improve timing performance. However, the buffer itself consumes power and it has been shown that power dissipation of buffers is significant. Although there are many buffer insertion algorithms that were able to optimize propagation delay with power constraint, most of them used the closed-form solution. Hence, in this paper, we present a formulation to compute dynamic power dissipation of buffers for application in dynamic programming buffer insertion algorithm. The proposed formulation allows dynamic power dissipation of buffers to be computed incrementally. The technique is validated by comparing the formulation with the standard closed-form dynamic power equation. The advantage of the proposed formulation is demonstrated through a series of experiments where it is applied in van Ginneken’s algorithm. The results show that the output of the proposed formulation is consistent with the standard closed-form formulation. Furthermore, it also suggests that the proposed formulation is able to compute dynamic power dissipation for buffer insertion algorithm with multiple buffer types.  

Derivation of Position-Probability Density for the Transient Nano-Tunnel Problem in SET

2010 ◽  
Author(s):  
Sheam-Chyun Lin ◽  
Hsien-Chang Shih ◽  
Fu-Sheng Chuang ◽  
Ming-Lun Tsai ◽  
Harki Apri Yanto ◽  
...  
Keyword(s):  
Probability Density ◽  
Error Function ◽  
Closed Form Solution ◽  
Form Solution ◽  
Single Electron ◽  
Mathematical Operation ◽  
Similarity Parameter ◽  
Set Up ◽  
Position Probability ◽  
Good Agreement

This theoretical investigation intends to study the nano-tunnel problem of the single electron transistor (SET), which is one of the most important components in the nano-electronics industry. With a combined effort of quantum mechanics and similarity parameter, the partial differential equation of transient position-probability density is attained and can be applied to predict the electron’s position inside the nano tunnel. Also, an appropriate set of the initial and the boundary conditions is set up in accordance to the actual electron behavior for solving this PDE of probability density function. Thereafter, a simple, closed-form solution for the probability density is obtained and expressed in terms of the error function for a new similarity variable η. Note that this analytic similarity solution is easy to perform the calculation and suitable for any further mathematical operation, such as the optimization applications. In addition, it is shown that these predications are reasonable and in good agreement to the physical meanings, which are evaluated from both microscopic and macroscopic viewpoints. In conclusions, this is an innovative approach by using the Schro¨dinger equation directly to solve the nano-tunnel problem. Moreover, with the aids of this analytic position-probability-density solution, it is illustrated that the free single electron in the SET’s tunnel can only appear at some specified regions, which are defined by a dimensionless parameter η within a range of 0 ≤ η ≤ 2. This result can be served as a valuable design reference for setting the practical manufacture requirement.

Flow Analysis and Modeling of Field-Controllable, Electro- and Magneto-Rheological Fluid Dampers

2005 ◽  
Vol 74 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Xiaojie Wang ◽  
Faramarz Gordaninejad
Keyword(s):  
Theoretical Model ◽  
Flow Analysis ◽  
Closed Form Solution ◽  
Nonlinear Behavior ◽  
Form Solution ◽  
Proposed Model ◽  
Fluid Dampers ◽  
Magneto Rheological ◽  
Er Fluid ◽  
Theoretical Results

This study combines a fluid mechanics-based approach and the Herschel-Bulkley constitutive equation to develop a theoretical model for predicting the behavior of field-controllable, magneto-rheological (MR), and electro-rheological (ER) fluid dampers. The goal is to provide an accurate theoretical model for analysis, design, and development of control algorithms of MR/ER dampers. Simplified explicit expressions for closed-form solution of the pressure drop across a MR fluid valve are developed. The Herschel-Bulkley quasi-steady flow analysis is extended to include the effect of fluid compressibility to account for the nonlinear dynamic behavior of MR/ER fluid dampers. The advantage of this model is that it only depends on geometric and material properties of the MR/ER material and the device. The theoretical results are validated by an experimental study. It is demonstrated that the proposed model can effectively predict the nonlinear behavior of field-controllable fluid dampers.

Vp/Vs ratio and dehydration reactions in subduction zones

2020 ◽  
Author(s):  
Nicolas Brantut ◽  
Emmanuel David
Keyword(s):  
Experimental Data ◽  
Subduction Zones ◽  
Fluid Pressure ◽  
Closed Form Solution ◽  
Form Solution ◽  
Strong Increase ◽  
Seismological Data ◽  
Dehydration Reactions ◽  
Model Predictions ◽  
Effective Medium Approach

<p>High Vp/Vs ratio is a commonly used diagnostic for elevated fluid pressure when interpreting seismological data. The physical basis for this interpretation comes from rock physical data and models of isotropic, cracked rocks. Here, we establish precise conditions under which this interpretation is correct, by using an effective medium approach for fluid-saturated rocks. While the usual result of an increasing Vp/Vs with increasing fluid-saturated porosity holds for crack-like pores, we find that Vp/Vs ratio is not always monotonically increasing with increasing fluid content if the porosity shape deviates from thin cracks, and if the initial Vp/Vs of the rock (without porosity) is already quite high. This is specifically the case of dehydrating rocks, where initial Vp/Vs may already be high (>1.9 for lizardite, for instance), and where the porosity created by the dehydration reaction may be in the form of elongated needles. The model predictions are supported by existing experimental data obtained during dehydration experiments in gypsum and lizardite, which both show a significant decrease in Vp/Vs as dehydration proceeds. Although no experimental data is yet availbale on antigorite, we make a prediction that antigorite dehydration may not lead to any strong increase in Vp/Vs ratio under typical subduction zone conditions. We present our theoretical results in the form of simple closed-form solution (valid asymptotically for a range of limiting cases), which should help guide the interpretation of Vp/Vs ratio from seismological data.</p>

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