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Full-Text Articles in Mechanical Engineering

Variable-Thickness Boundary Layers For Sliding Mode Control, Chyun-Chau Fuh Dec 2008

Variable-Thickness Boundary Layers For Sliding Mode Control, Chyun-Chau Fuh

Journal of Marine Science and Technology–Taiwan

Sliding mode control is a nonlinear feedback control technique which provides good robustness against modeling uncertainties and external disturbances. However, as the uncertainties or disturbances increase, a greater control input is required, and the control signal may cause an undesirable chattering phenomenon. In general, the further the system trajectory from the origin, the more violent the chattering effect. However, as the trajectory moves closer to the origin, the degree of chattering gradually reduces. As a result, even if an attempt is made to eliminate chattering by introducing a small constant boundary layer around the sliding surface, the chattering phenomenon may …


Developing A Convective Code With Vorticity Transport In Upwind Method, Je -Ee Ho Sep 2008

Developing A Convective Code With Vorticity Transport In Upwind Method, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The Navier-Strokes equations are usually used to solve the convective problems, however, to satisfy the conversation of mass, the uncertainty of pressure terms will easily trigger off the numerical divergence during the iterative process; which results in a calculating failure and makes the numerical solutions impossible. In this study, a vorticity–transport method that avoids the involvement of pressure terms by cross differentiate the governing equations and meets the flow conservation with stream function was proposed. With the aid of the upwind scheme and implicit method, an effective transformation from the partial differential equations into the vortex potential algebraic equations would …


Characteristic Study Of Mhd Minipump, Je -Ee Ho Sep 2008

Characteristic Study Of Mhd Minipump, Je -Ee Ho

Journal of Marine Science and Technology–Taiwan

The present study aims to develop and discuss the availability of the Magneto Hydrodynamics Minipump (MHD) as a miniaturizative part specified for precise manufacturing or medical application. Based on the MHD theory, an available working current (1.8A) induced by lower voltage (0-12V) and weaker magnetic intensity (0.04T) meets the need in mini-system operation. However, precise estimations of working capacity, maximum head, dynamic head, and static head in various electrolyte concentrations are necessary. Furthermore, this work also provides a simplified analytic model with a static balance between Lorentz force, surface tension force, and body force. Compared with analytic solutions and experimental …


Optimization Of Diffuser Valves, Chin-Tsan Wang, Pi-Cheng Chang, Chien-Cheng Huang Jun 2008

Optimization Of Diffuser Valves, Chin-Tsan Wang, Pi-Cheng Chang, Chien-Cheng Huang

Journal of Marine Science and Technology–Taiwan

In this study, the width of channel, D, and diffuser angle, , at given diffuser width whose value is 100 m will be studied for steady and unsteady flow conditions. By means of a series of numerical simulations, some findings for diffuser valve will be reported. The diffuser valve with a channel width of D = 300 m and diffuser angle =60º, is a better geometry because of its outstanding capability on suction production of net volume flow. Besides, the larger the Reynolds number is, the greater the suction amount of net volume flow will be. When the aspect ratio …


Investigation On The Blast Resistance Of A Stiffened Door Structure, Ming-Wei Hsieh, Jui-Pin Hung, De-Jen Chen Jun 2008

Investigation On The Blast Resistance Of A Stiffened Door Structure, Ming-Wei Hsieh, Jui-Pin Hung, De-Jen Chen

Journal of Marine Science and Technology–Taiwan

This study was aimed at investigating the blast resistance of a stiffened door structure. For this, a series of finite element transient analysis were performed to predict the dynamic response of blast resistant doors. Current results show that the stiffeners have sustained the majority of the explosive loadings. The effect of stiffener size on the stress state was rated in terms of the ratio of stiffener stress to plate stress, which was enhanced with the increase of web thickness of stiffener. Additional, the highest stresses were shown to occur at the transverse stiffeners near the hinged sides with a maximum …


Profile Design Of Piston Ring Using Inverse Method, Li-Ming Chu, Yuh-Ping Chang, Jung-Hua Yang Mar 2008

Profile Design Of Piston Ring Using Inverse Method, Li-Ming Chu, Yuh-Ping Chang, Jung-Hua Yang

Journal of Marine Science and Technology–Taiwan

This study aims to develop an algorithm for designing the piston ring profile and pressure distribution using an inverse method. The proposed algorithm needs to obtain load and boundary conditions for estimating not only a smooth curve in the piston ring profile, but also in the pressure distribution. The algorithm is developed from Reynolds integral and force balance equations. The least-squares error method, variational method, Gauss-Seidel method and Newton-Raphson method are employed to calculate the piston ring profile. Simulation results reveal that the greater the degree of the polynomial function used, the greater the maximum pressure ( Pmax ), load …


Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu Jun 2007

Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu

Journal of Marine Science and Technology–Taiwan

Nowadays, the active suspension is the key technology for vehicles to achieve both ride comfort and control performance. In this paper, a new 1/4T servo-hydraulic vehicle active suspension system is developed and two control schemes are utilized. The first one is a conventional PID controller obtained from Ziegler-Nichols method and the second one is the neural network controller. Though these two controllers are quite simple and not new, it is still worth mentioning that this paper emphasizes on the engineering aspects including the design of a servo-hydraulic test rig, the implementation technology of the controllers and the subsequent experimental study. …


Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu Jun 2007

Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu

Journal of Marine Science and Technology–Taiwan

In this research, we have experimented with two centrifugal fans with the same geometrical configuration. These two fans are designed to rotate at different speeds driven with the same voltage. The Particle Image Velocimetry (PIV) method is applied to measure the instantaneous flow fields at the near-exit region. The AMCA 210 wind tunnel is used to find the efficiency and the performance coefficients. The velocity vectors, streamlines, vorticity contours, velocity distributions, flow rate, and performances are also presented and discussed. We find that higher rotation speed yields better efficiency.


Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju Jun 2007

Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju

Journal of Marine Science and Technology–Taiwan

This study attempts to validate and analyze the mathematical models of the plowing dynamics and trajectory curve for tiller and cultivation blades of a rotary cultivator. Both blades are extensively used in Taiwan. The blade must be protected from intertwisting to ensure high efficiency and uniform resistance of the plow to soil. Theoretical and calculated cutting angles are found to be 85.88° and 84.28°, respectively, while the theoretical and calculated edge-curve angles are 59.70° and 58.31°. The present data confirmed that the tiller blades developed by local companies are suitable for the plowing environment in Taiwan. In order to reduce …


Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li Apr 2007

Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li

Journal of Marine Science and Technology–Taiwan

The stochastic chaotic motion and the threshold intensity of the external excitation force for onset of chaos of the ships in random beam waves are studied by the nonlinear stochastic dynamics theory. The random differential equation of ships’ rolling motion is established with considering the nonlinear damping, nonlinear restoring moment and the white noise wave excitation. The random Melnikov mean-square criterion is used to determine the threshold intensity for onset of chaos. The probability density function of the rolling response is calculated through solving the stochastic differential equations by applying the path integral method in the chaotic region. It is …


Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young Apr 2007

Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young

Journal of Marine Science and Technology–Taiwan

The vortex in the flow field will isolate the space to further reduce the indoor air exchange and convective efficiency. The Coanda vortex accompanied by the inlet jet usually has the most active effect on the flow field. Both its location and scalar size which are primary determined by the strength of the injected flow and the arrangement of inlet; outlet will deeply affect the air-exchange volume, even reduce the available ventilation space. A 2-D turbulent model with SIMPLE method is set up to simulate the air motion of indoors; it can easily describe the working of Coanda vortex in …


The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young Feb 2007

The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young

Journal of Marine Science and Technology–Taiwan

An appropriate ventilation system design not only increases the indoor ventilation effect but effectively improves the particle concentration distribution. The locations of indoor furniture are used to analyze the indoor airflow and particle distribution by numerical skill in this study. Also, a 45 cm × 45 cm × 45 cm chamber is setup as experiment apparatus which is made by acrylic resin board with 16 holes connected to supply air flow. In order to simulate the furniture effect, some wooden blocks are located at the chamber. The temperature and humidity sensors are connected to the data acquisition system with a …


Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang Feb 2007

Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang

Journal of Marine Science and Technology–Taiwan

For an internally reversible refrigerant plant, Bejan proposed an optimal way of dividing the area ratio of heat transfer for the hot end and cold end heat exchangers. In the present study, an optimal design of a refrigeration plant has been developed by considering both the external and internal irreversibilities. The internal irreversibility is modeled by a heat bypass which represents the actual internal heat leak and the friction losses due to mechanism movement. A more general formulation than previous study of optimal area-ratio is obtained in this study. For the case of no internal irreversibility, this formulation is exactly …


Averaged Inertia Principle For Non-Newtonian Squeeze Films In Wide Parallel Plates: Couple Stress Fluid, Jaw-Ren Lin, Chi-Ren Hung, Rong-Fang Lu Sep 2006

Averaged Inertia Principle For Non-Newtonian Squeeze Films In Wide Parallel Plates: Couple Stress Fluid, Jaw-Ren Lin, Chi-Ren Hung, Rong-Fang Lu

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the combined effects of non-Newtonian couple stresses and convective fluid inertia forces upon the squeeze film characteristics of two wide parallel plates are investigated by using the averaged inertia principle. A numerical solution of the film height versus response time is calculated by using the fourth-order Runge-Kutta method. Compared to the Newtonian-lubricant non-inertia case of Hamrock [4], the qualitative effects of couple stresses and convective inertia forces provide an increase in the film pressure, the load capacity and the response time. Moreover, the quantitative effects are more pronounced for wide parallel plates …


Dynamic Characteristics Of Wide Exponential Film-Shape Slider Bearings Lubricated With A Nonnewtonian Couple Stress Fluid, Jaw-Ren Lin, Rong-Fang Lu, Chi-Ren Hung Jun 2006

Dynamic Characteristics Of Wide Exponential Film-Shape Slider Bearings Lubricated With A Nonnewtonian Couple Stress Fluid, Jaw-Ren Lin, Rong-Fang Lu, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the nonNewtonian effects of couple stress fluids upon the dynamic characteristics of wide exponential-shaped slider bearings are presented in this paper. To take into account the couple stress effects arising from a Newtonian lubricant blended with various additives, the nonNewtonian couple-stress dynamic Reynolds-type equation is applied to calculate the bearing dynamics. According to the results obtained, the effects of couple stresses signify a decrease in the friction parameter and the volume flow rate, as well as an increase in the loadcarrying capacity, the dynamic stiffness coefficient and the dynamic damping coefficient for …


Reinforcing Effects And Mechanical Properties Of Rc Beam With Cfs Under Static And Running Loads, Ming-Chien Hsu, Tadashi Abe, Tetsukazu Kida, Toshiaki Sawano, Kazuhiko Minakuchi Jun 2006

Reinforcing Effects And Mechanical Properties Of Rc Beam With Cfs Under Static And Running Loads, Ming-Chien Hsu, Tadashi Abe, Tetsukazu Kida, Toshiaki Sawano, Kazuhiko Minakuchi

Journal of Marine Science and Technology–Taiwan

Through a series of experiments on RC beams reinforced with the carbon fiber sheet (CFS) under the static and running loads, the authors verified the effects of the aspect ratio (ratio of beam width to depth) and CFS reinforcement on the failure mechanism. The experiments revealed that: (1) CFS can effectively reinforce beams subjected to static loads in the flexural region, and increase the strength of beams subjected to running loads but such beams failed in shear, and (2) the tensile strength of CFS is greatly influenced by the aspect ratio. The authors evaluated how the aspect ratio influences the …


Laminar Film Condensation On A Horizontal Plate In A Porous Medium With Surface Tension Effects, Tong-Bou Chang Dec 2005

Laminar Film Condensation On A Horizontal Plate In A Porous Medium With Surface Tension Effects, Tong-Bou Chang

Journal of Marine Science and Technology–Taiwan

The problem of steady filmwise condensation on a finite-size horizontal plate embedded in a porous medium is studied for the case in which a cold plate faces upwards with a dry saturation vapor. Due to the effects of surface tension forces, there is a two-phase zone lying between the liquid film and the vapor zone. As in classical filmwise condensation problems, it is assumed that; (a) the inertia within the liquid film is negligible, and (b) the properties of porous medium, dry vapor, and condensate are constant. A dimensionless parameter Boc is introduced to characterize liquid flow due to surface …


A Note On Grashof’S Theorem, Wen-Tung Chang, Chen-Chou Lin, Long-Iong Wu Dec 2005

A Note On Grashof’S Theorem, Wen-Tung Chang, Chen-Chou Lin, Long-Iong Wu

Journal of Marine Science and Technology–Taiwan

In this paper, Grashof’s theorem is justified from the perspective of the occurrence of stationary configurations and uncertainty configurations of four-link chains. The link length relations at stationary configurations and uncertainty configurations are examined in detail based on the triangle inequality, and then the conditions for the existence of a crank and a change point are deduced.


A Study Of Non-Linear Vibrational Behavior Of Cracked Structures By The Finite Element Method, Tzuo-Liang Luo, James Shih-Shyn Wu, Jui-Pin Hung Sep 2005

A Study Of Non-Linear Vibrational Behavior Of Cracked Structures By The Finite Element Method, Tzuo-Liang Luo, James Shih-Shyn Wu, Jui-Pin Hung

Journal of Marine Science and Technology–Taiwan

Numerical and experimental investigations provide a link to the location and size of cracks caused by natural vibrations. Cracks may generally result in the variation of structural stiffness and hence enable structures to vibrate nonlinearly. In order to understand the vibrational behavior of crack structures accurately, the study proposes a general and efficient algorithm based on the finite element assumptions and the bilinear vibrational theory. All formulae are derived from the time domain properly and may apply to the overall non-linear motion cycle completely. The contact effect is also considered by introducing the degree of penetration on the cracked surface. …


An Investigation Of Contact Path And Kinematic Error Of Face-Gear Drives, Tsang-Dong Chung, Yun-Yuan Chang Jun 2005

An Investigation Of Contact Path And Kinematic Error Of Face-Gear Drives, Tsang-Dong Chung, Yun-Yuan Chang

Journal of Marine Science and Technology–Taiwan

Based on the face-gear generation process, the analytical geometry of face-gear drive with its mathematical model for tooth contact analysis of face-gear and spur pinion meshing was derived. In this paper, contact path and transmission error due to assembly misalignment are analyzed by using the proposed mathematical model and the tooth contact analysis. The effects of assembly error along the axis of face-gear, misalignment of crossed and angular displacement between axes of a spur pinion and a face-gear are all investigated. The results are illustrated by several examples


Simulation And Assessment Of Air Impingement Cooling On Squared Pin-Fin Heat Sinks Applied In Personal Computers, Hwa-Chong Tien, Wei-Dong Huang Mar 2005

Simulation And Assessment Of Air Impingement Cooling On Squared Pin-Fin Heat Sinks Applied In Personal Computers, Hwa-Chong Tien, Wei-Dong Huang

Journal of Marine Science and Technology–Taiwan

The feasibility and effectiveness of air impingement cooling on pin-fin heat sinks applied in personal computers (PC) were investigated numerically in this study. The effects of fin height, fin width, base plate thickness of the heat sink, and ratio of the vertical spacing between the nozzle and the heat sink to jet diameter (z/D) were discussed in detail. For a PC with a P4, 2.8 GHz, 68.4 W CPU, it was found that the cooling effect by using air impingement on a heat sink with z/D = 4 and fin width 4.13 mm for the jet Reynolds number (Re) between …


Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu Aug 2004

Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu

Journal of Marine Science and Technology–Taiwan

According to the Stokes micro-continuum theory, the effects of couple stresses upon the steady-state performance of wide parabolicshaped slider bearings are presented in this paper. To account for the couple stress effects arising from a Newtonian lubricant blended with various additives, the modified non-Newtonian Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. Comparing with the traditional Newtonianlubricant case, the effects of couple stresses characterized by the couple stress parameter signify an improvement in the steady-state performance. Increasing values of the couple stress parameter increases the bearing load-carrying capacity and reduces the required volume flow …


Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang Aug 2004

Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang

Journal of Marine Science and Technology–Taiwan

In the present study, the atomization of a coaxial injector in the liquid/gas engine combustor was numerically investigated. Based on the wave instability analysis of the interface between liquid and gas, an atomization model for the high-speed liquid jets was established by coupling with the jet flow solutions. First, the wave instability was analyzed to predict the growth rates along the liquid jet surface by numerically solving the wave dispersion equation, while the governing equations of the liquid flow were solved for the formation of the liquid jet core and the variation of the liquid flow structure. Then, these two …


Application Of Genetic Algorithm To The Shape Optimization Of A Constrained Double-Chamber Muffler With Extended Tubes, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu Jun 2004

Application Of Genetic Algorithm To The Shape Optimization Of A Constrained Double-Chamber Muffler With Extended Tubes, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu

Journal of Marine Science and Technology–Taiwan

As the compact design of a muffler system within a constrained environment of a existing machine room becomes obligatory, it also becomes essential to maximize the acoustic performance of mufflers under space constraints. In this paper, the shape optimization of a double-chamber muffler with an extended tube is presented. The main characteristic of the solution methodology is the use of genetic algorithm (GA) as the optimizer. In the paper, the acoustic performance of sound transmission loss (STL) derived by transfer matrix is conjugated with the techniques of GA searching. A numerical case of noise elimination in full band noise is …


Analysis Of Dynamic Characteristics For Wide Slider Bearings With An Exponential Film Profile, Jaw-Ren Lin, Chi-Ren Hung Jun 2004

Analysis Of Dynamic Characteristics For Wide Slider Bearings With An Exponential Film Profile, Jaw-Ren Lin, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

Analysis of dynamic characteristics plays an important role in designing hydrodynamic bearings. Based upon the thin-film lubrication theory, the analysis of dynamic characteristics for a wide slider with exponential film profiles is presented when taking into account the bearing squeezing action. By applying a small perturbation technique to the dynamic Reynolds-type equation, both of the steadystate performance and the dynamic characteristics are then evaluated. Comparing with those of slider bearings with an inclined-plane film shape, higher values of the load-carrying capacity, stiffness coefficient and damping coefficient are predicted for the bearing with larger values of the inlet-outlet film ratio. These …


Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee Apr 2004

Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee

Journal of Marine Science and Technology–Taiwan

This paper deals with quasi-static coupled thermoelastic problems for multilayered spheres. Using the Laplace transform with respect to time, the general solutions of the governing equations are obtained in transform domain. The solution is obtained by using the matrix similarity transformation and inverse Laplace transform. We obtain solutions for the temperature and thermal deformation distributions for a transient state. It is demonstrated that the computational procedures established in this paper are capable of solving the generalized thermoelasticity problem of multilayered spheres.


Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai Apr 2004

Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai

Journal of Marine Science and Technology–Taiwan

The thickness and the attached area of the sound absorber are confined in the practical engineering design while the sound absorber is applied inside the machine room to eliminate the reverberant sound energy. The optimization of the shape of the absorber and the quantification of the exact area of the absorber (in order to meet the required value of sound pressure level (SPL) at the concerned receiving point) becomes essential. For purposes stated above, two powerful gradient techniques with a logical control algorithm are applied during the optimization of the sound absorption system. Both the optimization of shape and the …


Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu Apr 2004

Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu

Journal of Marine Science and Technology–Taiwan

Considering the effects of viscous shear stresses, a study of squeeze-film behavior between porous parallel plates with finite width is presented. Based upon the Brinkman model (BM), two general coupled Reynolds equations derived for curved surfaces [20] are applied to predict the two-dimensional squeeze-film pressure and thereafter the squeeze-film characteristics. The results show that the BM predicts quite different squeeze-film behaviors to those obtained by using the slip-flow model (SFM) and the Darcy model (DM). Comparing with the SFM, the viscous shear effects provide an increase in the load-carrying capacity and lengthen the response time of finite porous squeeze-film plates. …


The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung Apr 2004

The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

On the basis of the Stokes micro-continuum theory, the effects of couple stresses resulting from the lubricant blended with various additives upon the squeeze film behavior between a long cylinder and a plane surface are analyzed. Compared to the conventional Newtonianlubricant case, the couple stress effects characterized by the couple stress parameter signify an improvement in the squeeze film characteristics. Increasing values of the couple stress parameter increases the hydrodynamic load-carrying capacity and provides a longer time to prevent cylinder-plane surface contact. The approaching time of the cylinder in reducing the film thickness h m * = 1 to h …


Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee Feb 2004

Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee

Journal of Marine Science and Technology–Taiwan

Experiments show that pipe flows with large expansion angle and area ratio always accompany with significant amount of energy loss, actually energy loss ratios over 70% of incoming flow kinetic energy are commonplace. It is generally believed that all the energy loss is entirely due to viscous dissipation effect. In this paper, several interesting demonstrations have been given to prove the existence and importance of impact energy loss. Literally, impact energy loss is usually more important than viscous energy loss in many cases. In fact, the pipe expansion flow can be configured as high-speed flow ramming into low-speed flow and …