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 Title
 On the Drainage Vortices of Liquid in a Container with Two Outlets.
 Creator
 Stankovic, Radivoje, Su, TsungChow, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
 Abstract/Description

When a liquid drains through a hole in a container, a vortex may form between the surface and the drainage hole. An interesting phenomenon occurs in the presence of two drainage holes. Only one vortex forms, while the other hole will mostly drain as sink flow. In addition, the vortex can switch between one hole and the other with regular periodicity. The primary goal of this study is to measure this periodicity under varying conditions (height of water in the container, diameter of the...
Show moreWhen a liquid drains through a hole in a container, a vortex may form between the surface and the drainage hole. An interesting phenomenon occurs in the presence of two drainage holes. Only one vortex forms, while the other hole will mostly drain as sink flow. In addition, the vortex can switch between one hole and the other with regular periodicity. The primary goal of this study is to measure this periodicity under varying conditions (height of water in the container, diameter of the drainage holes, and distance between drainage holes). Additionally, a study concerning the volume flow rates of vortical vs. sink flow out of the drainage holes was conducted. In the case of two drainage holes, when the height of the water was decreased in the container, the diameter of drainage holes decreased, or the distance between drainage holes was increased, the switching period was shown to decrease.
Show less  Date Issued
 2020
 PURL
 http://purl.flvc.org/fau/fd/FA00013572
 Subject Headings
 Drainage, Vortexmotion
 Format
 Document (PDF)
 Title
 Separation flow around airfoil with upstream disturbance by discrete vortex method.
 Creator
 Li, Feng., Florida Atlantic University, Su, TsungChow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The discrete vortex method was applied to the calculation of separation flow past NACA 4412 airfoil: Vortex panel was used to represent the body surface and discrete vortices were used to model the wake. Generally the uniform upstream condition is used in the calculation of separation flow. But actually an airfoil could move in wake of other airfoils or disturbed fluid. In this thesis, discrete vortices were used to model the upstream disturbance to investigate the effect of upstream...
Show moreThe discrete vortex method was applied to the calculation of separation flow past NACA 4412 airfoil: Vortex panel was used to represent the body surface and discrete vortices were used to model the wake. Generally the uniform upstream condition is used in the calculation of separation flow. But actually an airfoil could move in wake of other airfoils or disturbed fluid. In this thesis, discrete vortices were used to model the upstream disturbance to investigate the effect of upstream disturbance to the pressure, lift and drag coefficients around the airfoil. Also the animation of separation flow was made on HP workstation using "Starbase" computer graphic package to study the separation process.
Show less  Date Issued
 1991
 PURL
 http://purl.flvc.org/fcla/dt/14739
 Subject Headings
 Vortexmotion, Fluid dynamics
 Format
 Document (PDF)
 Title
 Design and evaluation of a swirling flow combustion system.
 Creator
 Li, Ceji., Florida Atlantic University, Moslemian, Davood, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A swirling flow combustion system has been designed and constructed. An integral laser Doppler velocimeter is constructed for the investigations of fluid mechanics aspects of a swirling flow combustor. The combustor consists of one fuel flow and two swirled air flows. The inner air flow has a fixed swirling strength and the outer air flow has an adjustable swirler. Both counterswirl and coswirl flows with variable swirl strength can be generated. Premixed or nonpremixed combustion can be...
Show moreA swirling flow combustion system has been designed and constructed. An integral laser Doppler velocimeter is constructed for the investigations of fluid mechanics aspects of a swirling flow combustor. The combustor consists of one fuel flow and two swirled air flows. The inner air flow has a fixed swirling strength and the outer air flow has an adjustable swirler. Both counterswirl and coswirl flows with variable swirl strength can be generated. Premixed or nonpremixed combustion can be investigated on this system. Evaluation of the swirling combustion system and performance check of the velocity measurement system are conducted. Detailed time mean and fluctuating flow measurements are obtained for coswirl and counterswirl conditions with the LDV system. A central recirculation zone is observed in both swirl conditions, but the size in counterswirl is much smaller. The reasons for the difference are discussed.
Show less  Date Issued
 1991
 PURL
 http://purl.flvc.org/fcla/dt/14767
 Subject Headings
 Fluid dynamics, Vortexmotion, Combustion chambers
 Format
 Document (PDF)
 Title
 Vortex street wakes downstream of truncated and full cylinders in a rotating fluid.
 Creator
 Leader, Bram., Florida Atlantic University, Marshall, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

An experimental study has been conducted to examine the flow field about and the wake behind truncated cylindrical obstacles of varying height, which are towed through a fluid with a free surface in a rotating system. The results show the development of a vortex streettype wake downstream of the obstacle for retrograde (westward) flows, even for very small ratios of obstacle height to water layer depth. For short obstacles, a pronounced backward flowing jet is observed, which impinges on the...
Show moreAn experimental study has been conducted to examine the flow field about and the wake behind truncated cylindrical obstacles of varying height, which are towed through a fluid with a free surface in a rotating system. The results show the development of a vortex streettype wake downstream of the obstacle for retrograde (westward) flows, even for very small ratios of obstacle height to water layer depth. For short obstacles, a pronounced backward flowing jet is observed, which impinges on the Taylor column from downstream. Prograde (eastward) flows are found to have a meandering wake that extends farther than eight obstacle diameters downstream and do not exhibit backjetting or vortex street formation. Upwelling is believed to occur within the side boundary layers of the Taylor column, which could play a significant role in deep water production in the ocean.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fcla/dt/14827
 Subject Headings
 Taylor vortices, Fluid dynamics, Vortexmotion
 Format
 Document (PDF)
 Title
 A numerical study of bluff body aerodynamics by vortex method.
 Creator
 He, Fusen., Florida Atlantic University, Su, TsungChow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

Vortex methods are gridfree; therefore, their use avoids a number of shortcomings of Eulerian, gridbased numerical methods for solving high Reynolds number flow problems. These include such problems as poor resolution and numerical diffusion. In vortex methods, the continuous vorticity field is discretized into a collection of Lagrangian elements, known as vortex elements. Vortex elements are free to move in the flow field which they create. The velocity field induced by these vortex...
Show moreVortex methods are gridfree; therefore, their use avoids a number of shortcomings of Eulerian, gridbased numerical methods for solving high Reynolds number flow problems. These include such problems as poor resolution and numerical diffusion. In vortex methods, the continuous vorticity field is discretized into a collection of Lagrangian elements, known as vortex elements. Vortex elements are free to move in the flow field which they create. The velocity field induced by these vortex elements is a solution to the NavierStokes equation, and in principle the method is suitable for high Reynolds number flows. In this dissertation, viscous vortex element methods are studied. Some modifications are developed. Discrete vortex element methods have been used to solve the NavierStokes equations in high Reynolds number flows. Globally satisfactory results have been obtained. However, computed pressure fields are often inaccurate due to the significant errors in the surface vorticity distribution. In addition, different ad hoc assumptions are often used in different proposed algorithms. In the present study, improvements are made to better represent the nearwall vorticity when obtaining numerical solutions for the NavierStokes equations. In particular, we split the boundary vortex sheet into two parts at each time step. One part remains a vortex sheet lying on the boundary of the solid body, and the other enters into the flow field as a free vortex element with a uniformly distributed vorticity. A set of kinematic relationships are used to determine the two appropriate portions of the split, and the position of the vortex element to be freed at the time of release. Another improvement is to include the nonlinear acceleration terms in the governing equations near the solid boundary when evaluating the surface pressure distribution. The aerodynamic force coefficients can then be obtained by summing up the pressure forces. By comparing the computed surface vorticities, surface pressures and aerodynamics force coefficients with existing numerical/experimental data in the cases of viscous flow around a circular cylinder, an aerofoil, and a bridge deck section, it is shown that the present approach is more accurate in modelling the flow features and force coefficients without making different ad hoc assumptions for different geometries. The computation is efficient. It can be useful in the study of the unsteady fluid flow phenomenon in practical engineering problems.
Show less  Date Issued
 1998
 PURL
 http://purl.flvc.org/fcla/dt/12574
 Subject Headings
 Vortexmotion, Fluid mechanics, Viscous flow
 Format
 Document (PDF)
 Title
 Interaction of vortex sheet with a finite vortex.
 Creator
 Viswanathan, K. S., Florida Atlantic University, Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The rollup of a vortex sheet of elliptic span loading in the presence of a vortex of finite core size is studied in the Trefftz plane. The vorticity in the finite vortex is taken to be uniform and sign opposite to that of the sheet and the flow is assumed to be inviscid and incompressible. A numerical scheme is developed to determine the evolution of (a) the finite vortex using the Contour Dynamics technique, (b) the vortex sheet using an algorithm developed by Krasny. The interaction is...
Show moreThe rollup of a vortex sheet of elliptic span loading in the presence of a vortex of finite core size is studied in the Trefftz plane. The vorticity in the finite vortex is taken to be uniform and sign opposite to that of the sheet and the flow is assumed to be inviscid and incompressible. A numerical scheme is developed to determine the evolution of (a) the finite vortex using the Contour Dynamics technique, (b) the vortex sheet using an algorithm developed by Krasny. The interaction is shown to substantially affect the development of the vortex sheet rollup. The vortex sheet undergoes significant deformation at the rolling up tip region due to its devouring the vortex patch as well as due to the formation of secondary rollup features on the sheet. These features are believed to be important in inhibiting rollup considerably. The interaction is quantified by using a criterion developed to measure the extent of the tip vortex rollup and its characteristics are studied for a range of flow parameters. The strength of the rolling up tip region of the vortex sheet is found to be highly dependent on the location and the vorticity in the finite vortex.
Show less  Date Issued
 1994
 PURL
 http://purl.flvc.org/fcla/dt/15048
 Subject Headings
 Turbulence, Whirlwinds, Vortexmotion, Wakes (Aerodynamics)
 Format
 Document (PDF)
 Title
 Sound generated due to vortical flow past a forward facing step.
 Creator
 Gundlapalli, Ravishankar., Florida Atlantic University, Dhanak, Manhar R.
 Abstract/Description

The sound field associated with the motion of 2dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate lowfrequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex...
Show moreThe sound field associated with the motion of 2dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate lowfrequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex structure evolves in the nonuniform flow in the vicinity of the step and under certain conditions is found to undergo significant deformation of its core structure. The far field acoustic pressure is found to be a strong function of vortex motion in the vicinity of the step. Results for the vortex trajectory and the associated acoustic pressure are presented for a variety of flow parameters.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fau/fd/FADT14825
 Subject Headings
 Underwater acoustics, Vortexmotion, Eddies, Hydrodynamics
 Format
 Document (PDF)
 Title
 Effect of applied periodic strain on coherent structures in a turbulent boundary layer.
 Creator
 Neravetla, Bharath Reddy, Florida Atlantic University, Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The effect of applied periodic straining field on the behavior of coherent vortical structures in the turbulent boundary layer is studied. In particular, the coherent vortical longitudinal structures in the turbulent boundary layer in the form of isolated vortices or in the form of pairs of counterrotating vortices is considered. The effect on the pressure fluctuations on the wall due to the applied periodic strain is studied. A numerical method using Contour Dynamics technique and...
Show moreThe effect of applied periodic straining field on the behavior of coherent vortical structures in the turbulent boundary layer is studied. In particular, the coherent vortical longitudinal structures in the turbulent boundary layer in the form of isolated vortices or in the form of pairs of counterrotating vortices is considered. The effect on the pressure fluctuations on the wall due to the applied periodic strain is studied. A numerical method using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of these structures in time. The pressure fluctuations on the wall are calculated making use of the unsteady Bernoulli's equation. The various parameters associated with the coherent structures in the turbulent boundary layer such as the strength of the vortices, their distance from the wall, separation distance between counterrotating vortices, the frequency of the applied straining field, the magnitude of the straining field and the stretching rate are varied to study the resultant pressure fluctuations. It is observed that at low applied frequencies, there are high modulations in the surface pressure fluctuations, and at higher applied frequencies of straining field there is reduction in surface pressure fluctuations in the boundary layer.
Show less  Date Issued
 1994
 PURL
 http://purl.flvc.org/fcla/dt/15020
 Subject Headings
 Vortexmotion, Turbulent boundary layer, PressureMeasurement
 Format
 Document (PDF)
 Title
 Experimental study of flow over a bundle of cylinders.
 Creator
 Khuc, Hiep Hieu., Florida Atlantic University, Su, TsungChow, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The drag reduction by vortex fusion was investigated. A comparison of flow over a bundle of cylinders in uniform and in disturbed currents was performed in a water channel. The model was subjected to cross flow. A thin cylindrical wire located nearby upstream and leveled at half the height of the test model was used as a source of disturbance. A hydrogen bubble technique was utilized to observe the flow pattern. The accumulation of vortices at stagnating regions in front of a bundle of...
Show moreThe drag reduction by vortex fusion was investigated. A comparison of flow over a bundle of cylinders in uniform and in disturbed currents was performed in a water channel. The model was subjected to cross flow. A thin cylindrical wire located nearby upstream and leveled at half the height of the test model was used as a source of disturbance. A hydrogen bubble technique was utilized to observe the flow pattern. The accumulation of vortices at stagnating regions in front of a bundle of cylinders transformed into a counterrotated curl at leading edges of each leading cylinder in the bundle. Measurements were carried out by a computerized data acquisition system. Drag coefficient measurements, digital spectral and fourier analyses were also performed. Results have shown that a drag reduction can be obtained by introducing a thin cylindrical wire in front of the stagnation.
Show less  Date Issued
 1994
 PURL
 http://purl.flvc.org/fcla/dt/15026
 Subject Headings
 Vortexmotion, Fluid dynamics, Cylinders, Fourier transformations, Hydrodynamics
 Format
 Document (PDF)
 Title
 Nonlinear convection of a vortex sheet past a cascade of airfoils.
 Creator
 van den Berg, Stanislas Franck., Florida Atlantic University, Glegg, Stewart A. L.
 Abstract/Description

The interaction of rotor turbulence with the stator is currently believed to be the predominant mechanism of noise radiation from turbofans in aircraft engines. This thesis presents a general method to compute unsteady 2D potential flows past a cascade of airfoils. The procedure uses source and vortex distributions on the surface of the airfoils, creation of wakes downstream of the airfoils and nonlinear convection of the perturbed flow. These features are designed to satisfy a condition of...
Show moreThe interaction of rotor turbulence with the stator is currently believed to be the predominant mechanism of noise radiation from turbofans in aircraft engines. This thesis presents a general method to compute unsteady 2D potential flows past a cascade of airfoils. The procedure uses source and vortex distributions on the surface of the airfoils, creation of wakes downstream of the airfoils and nonlinear convection of the perturbed flow. These features are designed to satisfy a condition of noflow through the surface of the airfoils and the Kutta condition at the trailing edge of each of these airfoils. The investigation proves the importance of applying the Kutta condition. It was also shown that an infinite cascade is well approximated by a small number of airfoils and that the nonlinear rather than linear convection of vorticity has a large effect on the spectrum of the unsteady lift of an airfoil.
Show less  Date Issued
 1998
 PURL
 http://purl.flvc.org/fcla/dt/15586
 Subject Headings
 Vortexmotion, Cascades (Fluid dynamics), Unsteady flow (Fluid dynamics)
 Format
 Document (PDF)
 Title
 Tearing of an aligned vortex by a current difference in twolayer quasigeostrophic flow.
 Creator
 Parthasarathy, Balaji., Florida Atlantic University, Marshall, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A study of twolayer quasigeostrophic vortex flow is performed to determine the effect of a current difference between the layers on a vortex initially extending through both the layers. In particular, the conditions under which the current difference can 'tear' the vortex are examined. In the first set of flows studied, the current difference is generated by a (stronger) third vortex in the upper layer located at a large distance from the (weaker) vortex under study. A set of flows are also...
Show moreA study of twolayer quasigeostrophic vortex flow is performed to determine the effect of a current difference between the layers on a vortex initially extending through both the layers. In particular, the conditions under which the current difference can 'tear' the vortex are examined. In the first set of flows studied, the current difference is generated by a (stronger) third vortex in the upper layer located at a large distance from the (weaker) vortex under study. A set of flows are also considered in which an ambient geostrophic current difference is produced by a nonuniform background potential vorticity field. The results of the study will be useful in determining the conditions under which large geophysical vortex structures, such as cyclones and ocean rings, can extend to large depths even though the mean currents in the ambient flow change significantly along the vortex length.
Show less  Date Issued
 1993
 PURL
 http://purl.flvc.org/fcla/dt/14909
 Subject Headings
 Vortexmotion, Fluid dynamics, Boundary layer control, Flow visualization
 Format
 Document (PDF)
 Title
 Computations of normal vortex interaction with blades and circular cylinders.
 Creator
 Yalamanchili, Ramakrishna., Florida Atlantic University, Marshall, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A numerical model for the simulation of threedimensional normal bladevortex interaction has been developed to study the bending and variation of core radius of the vortex due to the influence of the blade and the subsequent unsteady force on the blade. For thin blades, a procedure to enable instantaneous cutting of the vortex has been employed to study the vortex response to cutting. The vortex is represented by a filament model which includes axial flow within the core and nonuniform core...
Show moreA numerical model for the simulation of threedimensional normal bladevortex interaction has been developed to study the bending and variation of core radius of the vortex due to the influence of the blade and the subsequent unsteady force on the blade. For thin blades, a procedure to enable instantaneous cutting of the vortex has been employed to study the vortex response to cutting. The vortex is represented by a filament model which includes axial flow within the core and nonuniform core area. The vortex is convected with selfinduced velocities given by the BiotSavart line integral, and the effect of the cylinder is obtained using a vortex sheet panel method. The governing equations for the vortex axial velocity have a form similar to that of the onedimensional gas dynamics equations and admit "shocklike" discontinuities. The results indicate that the amount of vortex bending due to interaction with the blade is primarily dependent on the ratio of blade thickness T to ambient vortex core radius sigma o, although for a given amount of bending of the vortex axis, increase in cylinder forward speed results in a decrease in vortex core radius. For blades with T/sigma o < 0(1), very little bending is observed for attack angles under the stall limit. In the case of vortex cutting by a blade, vortex shocks and expansion waves are observed to propagate on the vortex axis away from the blade.
Show less  Date Issued
 1993
 PURL
 http://purl.flvc.org/fcla/dt/14985
 Subject Headings
 Helicopters, BladesNoise, Rotors (Helicopters), Vortexmotion
 Format
 Document (PDF)
 Title
 Stability of an elliptical vortex in a timedependent strain field.
 Creator
 Marshall, Marilyn P., Florida Atlantic University, Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A theoretical study of the stability of twodimensional elliptical vortices in a timedependent, periodically varying external straining flow was conducted. The mean value of the oscillating straining flow was chosen so that the vortex would be stationary in the absence of fluctuations of the external field about the mean. If the frequency of straining is near to the natural frequency of the vortex for smallamplitude oscillations of the vortex core, so that the vortex is forced near its...
Show moreA theoretical study of the stability of twodimensional elliptical vortices in a timedependent, periodically varying external straining flow was conducted. The mean value of the oscillating straining flow was chosen so that the vortex would be stationary in the absence of fluctuations of the external field about the mean. If the frequency of straining is near to the natural frequency of the vortex for smallamplitude oscillations of the vortex core, so that the vortex is forced near its natural frequency, a resonance occurs such that the aspect ratio of the elliptical core boundary initially oscillates with an amplitude that increases linearly with time. After an initial period of growth, the aspect ratio will either follow a bounded limit cycle at large time or it will elongate exponentially with time. The nonlinear evolution of the vortex at large time is studied numerically, and distinct regions of behavior in the parameter space for the vortex are obtained.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fcla/dt/14817
 Subject Headings
 VortexMotion, Fluid dynamicsMathematical models
 Format
 Document (PDF)
 Title
 Wind effect on supertall buildings using computational fluid dynamics and structural dynamics.
 Creator
 Assaad, Bilal, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

Supertall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 710 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of...
Show moreSupertall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 710 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of Computational Fluid Dynamics has created an additional layer of analysis and loading prediction alternative to conventional methods. The present document uses turbulence modeling and numerical algorithms by means of Reynoldsaveraged NavierStokes and Large Eddy Simulation equations applied to a square prismatic prototype structure in which its dynamic properties have also been investigated. With proper modeling of the atmospheric boundary layer flow, these numerical techniques reveal important aerodynamic properties and enhance flow visualization to structural engineers in a virtual environment.
Show less  Date Issued
 2015
 PURL
 http://purl.flvc.org/fau/fd/FA00004343, http://purl.flvc.org/fau/fd/FA00004343
 Subject Headings
 Boundary layer control, Buildings  Aerodynamics, Computational fluid dynamics, Structural dynamics  Data processing, Vortex motion
 Format
 Document (PDF)
 Title
 Investigation of trapped vortex combustion using hydrogenrich fuels.
 Creator
 Zbeeb, Khaled., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The combustion process of a fuel is a challenging subject when it comes to analyze its performance and resultant emissions. The main task of this study is to optimize the selection of a hydrogenrich fuel based on its performance and emissions. Computational Fluid Dynamics analysis is performed to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthesis gas....
Show moreThe combustion process of a fuel is a challenging subject when it comes to analyze its performance and resultant emissions. The main task of this study is to optimize the selection of a hydrogenrich fuel based on its performance and emissions. Computational Fluid Dynamics analysis is performed to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthesis gas. Correlation graphs for the trapped vortex combustor performance and NOx, CO, and CO2 emissions for various types of fuels with different compositions and heat of combustion values were established. Methane, Hydrogen and 10 different syngas fuels were analyzed in this study using computational fluid dynamics numerical method. The trapped vortex combustor that represents an efficient and compact combustor for flame stability was investigated. The TVC consists of a fore body and two after body disks . These components are all encircled with a Pyrex tube. The purpose of the after body disks is to create the vortex wakes that will enhance the combustion process and minimize the NOx emissions. The TVC CFD model was validated by comparing the CFD model results using propane fuel with existing experimental results that were established in Rome, Italy. The static temperature distribution and NOx, CO emissions, combustor efficiency and total pressure drop results of the three dimensional CFD model were similar to the experimental data. Effects of H2/CO and H2/CH4 ratios and the mass fraction of each constituent of syngas fuels and HydrogenMethane fuel mixture on the TVC performance and emissions were investigated., Moreover, the fuel injector Reynolds number and Lower heating values for Methane, Hydrogen and 10 syngas fuels on the TVC performance and emissions were also investigated. Correlation plots for the NOx, CO and CO2 emissions versus the fuel injector Reynolds number and low heating value were established. These correlation curves can be used as a fair design diagram to optimize the fuel selection process for aerospace and electrical power plant applications.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3334096
 Subject Headings
 Hydrogen as fuel, Research, Combustion chambers, Vortexmotion, Fluid dynamics
 Format
 Document (PDF)
 Title
 An experimental study of vortex response during cutting by a blade or cylinder.
 Creator
 Krishnamoorthy, Srikanth., Florida Atlantic University, Marshall, Jeffrey S., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

An experimental study of the vortex response to interaction with and cutting by a thin flat plate or circular cylinders of various diameters has been performed. The direction of motion of the flat plate (or circular cylinder) is normal to the vortex axis in the experiments. The vortex is generated by withdraw of fluid at an orifice at the bottom of an "inner cylinder" immersed in a rectangular tank, and the flow field is visualized with both water soluble and immiscible dyes. In the...
Show moreAn experimental study of the vortex response to interaction with and cutting by a thin flat plate or circular cylinders of various diameters has been performed. The direction of motion of the flat plate (or circular cylinder) is normal to the vortex axis in the experiments. The vortex is generated by withdraw of fluid at an orifice at the bottom of an "inner cylinder" immersed in a rectangular tank, and the flow field is visualized with both water soluble and immiscible dyes. In the experiments with circular cylinders, the bending of the vortex is compared to computational predictions from [15], and the mechanism of subsequent breakup of the vortex as it gets closer to the cylinder is studied. The vortex is observed to bend farther without breakup for larger forward speeds of the circular cylinder. Very little bending is observed when the vortex interacts with the flat plate, except for angles of attack exceeding the stall limit Following cutting of the vortex by the flat plate or circular cylinder, a vortex shock is observed to form and propagate up the vortex axis. No vortex shock is observed on the opposite side of the blade. The various forms of these vortex shocks have been photographed, and they appear very similar to travelling vortex breakdowns. The propagation speed of the shocks is compared to an analytical solution for instantaneous vortex cutting by a flat plate of zero thickness.
Show less  Date Issued
 1993
 PURL
 http://purl.flvc.org/fcla/dt/14977
 Subject Headings
 Vortexmotion, BladesNoise, Cylinders, Rotors (Helicopters), HelicoptersNoise
 Format
 Document (PDF)
 Title
 Numerical Simulation of a Flowfield Around a Hypersonic Missile with Lateral Jets.
 Creator
 Rodriguez, Daniel, Moslemian, Davood, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

This work uses computational fluid dynamics to study the flowfield around a hypersonic missile with two lateral jets to provide control in place of control surfaces. The jets exhaust an H2O2 mixture at Mach number of 2.9 with a jet pressure ratio of roughly 10,500. The jets are staggered axially and circumferentially in such a way to produce pitch and yaw. The flowfield of such a jet configuration is characterized at several angles of attack and the corresponding force coefficients and...
Show moreThis work uses computational fluid dynamics to study the flowfield around a hypersonic missile with two lateral jets to provide control in place of control surfaces. The jets exhaust an H2O2 mixture at Mach number of 2.9 with a jet pressure ratio of roughly 10,500. The jets are staggered axially and circumferentially in such a way to produce pitch and yaw. The flowfield of such a jet configuration is characterized at several angles of attack and the corresponding force coefficients and amplification factors are provided. The freestream air and H2O2 plume is treated as inert for the majority of the calculations. Special cases are treated with finite rate chemical kinetics and compared to the inert flowfield to ascertain the effects that chemical reactions have on the force coefficients. It was found that the flowfield was only slightly altered from the familiar one jet flowfield when the second jet is active. The flow topology and vortex structures tend to shift towards the second jet but the overall structure remains the same. The normal force amplification factors are close to unity over the range of angle of attack due to the thrust being so high with the two jet configuration having a lower amplification factor compared to firing a single jet. Treating the flowfield as chemically reacting did not affect the force values much: the difference being 0.3% for an angle of attack of 0°.
Show less  Date Issued
 2017
 PURL
 http://purl.flvc.org/fau/fd/FA00004893, http://purl.flvc.org/fau/fd/FA00004893
 Subject Headings
 Aerodynamics, Hypersonic., Nonequilibrium thermodynamics., AerothermodynamicsMathematica., Hypersonic planesDesign and constructionMathematical models., VortexmotionMathematical models.
 Format
 Document (PDF)