We discuss a taxonomy of different dynamical features in the ocean surface and provide some eddy ... more We discuss a taxonomy of different dynamical features in the ocean surface and provide some eddy and front statistics, as well as describing some events detected by several satellites and even with additional cruise observations and measurements, in the Northwest Mediter-ranean Sea area between 1996 and 2012. The structure of the flows are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale, RL. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, Langmuir cells, oil spills and tensioactive slicks that eventually allow the study of the self-similar structure of the turbulence. Depending on the surface wind and wave level, and also on the fetch. the bathimetry, the spiral parameters and the resolution of vortical features change. Previous descriptions did not include the new wind and buoyancy features. SAR images also show the turbulence structure of the coastal area and the Regions of Fresh Water Influence (ROFI). It is noteworthy tt such complex coastal field-dependent behavior is strongly influenced by stratification and rotation of the turbulence spectrum is observed only in the range smaller than the local Rossby deformation radius, RL. The measures of diffusivity from buoy or tracer experiments are used to calibrate the behavior of different tracers and pollutants , both natural and man-made in the NW Mediter-ranean Sea. Thanks to different polarization and intensity levels in ASAR satellite imagery, these can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar and fractal as a function of spill and slick parameters, environmental conditions and history of both oil releases and weather conditions. Eddy diffusivity map derived from SAR measurements of the ocean surface, performing a feature spatial correlation of the available images of the region are presented. Both the multi fractal discrimination of the local features and the diffusivity measurements are important to evaluate the state of the environment. The distribution of meso-scale vortices of size, the Rossby deformation scale and other dominant features can be used to distinguish features in the ocean surface. Multi-fractal analysis is then very usefull. The SAR images exhibited a large variation of natural features produced by winds, internal waves, the bathymetric distribution, by convection, rain, etc as all of these produce variations in the sea surface roughness so that the topological changes may be studied and classified. In a similar way bathimetry may be studied with the methodology described here using the coastline and the thalwegs as generators of local vertical vorticity.
The advance of a Rayleigh-Taylor front is described in Linden & Redondo (1991),[1-3] and may be s... more The advance of a Rayleigh-Taylor front is described in Linden & Redondo (1991),[1-3] and may be shown to follow a quadratic law in time where the width of the growing region of instability depends on the local mixing efficiency of the different density fluids that accelerate against each other g is the acceleration and A is the Atwood number defined as the diference of densities divided by their sum. This results show the independence of the large amplitude structures on the initial conditions the width of the mixing region depends also on the intermittency of the turbulence. Then dimensional analysis may also depend on the relevant reduced acceleration driven time and the molecular reactive time akin to Damkholer number and the fractal structure of the contact zone [2,4]. Detailed experiments and simulations on RT and RM shock induced fronts analized with respect to structure functions are able to determine which mechanisms are most effective in local mixing which increase the effective fractal dimension, as well as the effect of higher order geometrical parameters, such as the structure functions, in non-homogeneous fluids (Mahjoub et al 1998)[5]. The structure of a Mixing blob shows a relatively sharp head with most of the mixing taking place at the sides due to what seems to be shear instability very similar to the Kelvin-Helmholtz instabilities, but with sideways accelerations. The formation of the blobs and spikes with their secondary instabilities produces a turbulent cascade, evident just after about 1 non-dimensional time unit, from a virtual time origin that takes into account the linear growth phase, as can be seen by the growth of the fractal dimension for different volume fractions. Two-dimensional cuts of the 3D flow also show that vortex flows have closed or spiral streamlines around their core. Examples of such flows can be also seen in the laboratory, for example at the interface of atwo-layer stratified fluid in a tank in which case streamlines are more regular. Mixing in turbulent flows remains less well understood, and in spite research some basic problems are still virtually unexplored.
Local Diffusion and the topological structure of vorticity and velocity fields is measured in the... more Local Diffusion and the topological structure of vorticity and velocity fields is measured in the transition from a homogeneous linearly stratified fluid to a cellular or layered structure by means of convective cooling and/or heating. Patterns arise by setting up a convective flow generated by an array of Thermoelectric devices (Peltier/Seebeck cells) these are controlled by thermal PID generating a buoyant heat flux. The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
Local Diffusion and the topological structure of vorticity and velocity fields is measured in the... more Local Diffusion and the topological structure of vorticity and velocity fields is measured in the transition from a homogeneous linearly stratified fluid to a cellular or layered structure by means of convective cooling and/or heating. Patterns arise by setting up a convective flow generated by an array of Thermoelectric devices (Peltier/Seebeck cells) these are controlled by thermal PID generating a buoyant heat flux. The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
Design and operation of thermoelectric coolers and heaters as well as the fluid mechanics of conv... more Design and operation of thermoelectric coolers and heaters as well as the fluid mechanics of convection is important [1]. We present a university-industrial colaboration that developed transient Thermoelectric driven convective models based on the control of thermal boundary conditions and flow measurements inside a closed enclosure for didactic uses. The coupling of heat transfer and electric conduction within semiconductors is important and takes into account all thermoelectric effects, including Joule and Seebeck heating, Thomson effect, Peltier effect and Fourier's heat conduction. We present a Thermoelectric driven heating and cooling experimental device in order to map the different transitions between two dimensional convection in an enclosure and the 3 D complex flows. The size of the box is of 0.2 x 0.2 x 0.1 m and the heat sources or sinks can be regulated both in power and sign [2,3]. The buoyancy driven flows are generated by Seebeck and Peltier effects in 4 to 40 wall positions. The parameter range of convective cell array varies strongly with the topology of the boundary conditions and buoyancy [4]. At present side and vertical heat fluxes are considered and estimated as a function of Rayleigh, Peclet and Nusselt numbers, but the tilting possibilities of the BEROTZA built experimental device also allow to heat/cool at any angle [5,6] (Redondo 1995, Redondo et al.2013). Fluid visualizations are performed by PIV, Particle tracking and shadowgraph/schliering [4]. Thermoelectric coolers offer the potential to better control and enhance the cooling of electronic modules to regulate operating temperatures or to allow higher power. Thermoelectric coolers are limited by the maximum heat fluxes and have lower coefficient of performance (COP) but offer a wide range of boundary fluid control. Environmental and Engineering Fluid Mechanics laboratories at university or professional schools may incorporate student practical work in several of many fields that need understanding such as:
Design and operation of thermoelectric coolers and heaters that may be used in detailled laborato... more Design and operation of thermoelectric coolers and heaters that may be used in detailled laboratory experiments of buoyancy driven trurbulence, as well as in the general fluid mechanics of convection is important, there seems to be a lack of comparison between numerical models of turbulent flows (Including Kinematic Simulation and DNS) and non-homogeneous experiments. [1-3] We present the results of a university-industrial colaboration that developed a Fluid Dynamic Didactic Apparatus able to model steady and transient Thermoelectric driven convective models based on the control of thermal boundary conditions and also optimized to perform flow measurements inside a closed enclosure. The Thermoelectric Convection Didactic Device (TCDD) presented here is basically designed for a range of didactic uses, but a wide range of innovative research options are available, both in the small 4x4 device shown in figure 1 and in larger and higher power equipments. We present here both the thermoelectric and the fluid flow description of the TCDD. The coupling of heat transfer and electric conduction within the semiconductor Thermal assemblies is important and takes into account the local thermoelectric effects, including Joule and Seebeck heating, Thomson effect, Peltier effect and Fouriers heat conduction. The macroscale heating cooling equations are presented together with the calibration and flow characteristics of the thermolectric convective devices shown only for an example configuration, but many other are possible.
We discuss a taxonomy of different dynamical features in the ocean surface and provide some eddy ... more We discuss a taxonomy of different dynamical features in the ocean surface and provide some eddy and front statistics, as well as describing some events detected by several satellites and even with additional cruise observations and measurements, in the Northwest Mediter-ranean Sea area between 1996 and 2012. The structure of the flows are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale, RL. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, Langmuir cells, oil spills and tensioactive slicks that eventually allow the study of the self-similar structure of the turbulence. Depending on the surface wind and wave level, and also on the fetch. the bathimetry, the spiral parameters and the resolution of vortical features change. Previous descriptions did not include the new wind and buoyancy features. SAR images also show the turbulence structure of the coastal area and the Regions of Fresh Water Influence (ROFI). It is noteworthy tt such complex coastal field-dependent behavior is strongly influenced by stratification and rotation of the turbulence spectrum is observed only in the range smaller than the local Rossby deformation radius, RL. The measures of diffusivity from buoy or tracer experiments are used to calibrate the behavior of different tracers and pollutants , both natural and man-made in the NW Mediter-ranean Sea. Thanks to different polarization and intensity levels in ASAR satellite imagery, these can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar and fractal as a function of spill and slick parameters, environmental conditions and history of both oil releases and weather conditions. Eddy diffusivity map derived from SAR measurements of the ocean surface, performing a feature spatial correlation of the available images of the region are presented. Both the multi fractal discrimination of the local features and the diffusivity measurements are important to evaluate the state of the environment. The distribution of meso-scale vortices of size, the Rossby deformation scale and other dominant features can be used to distinguish features in the ocean surface. Multi-fractal analysis is then very usefull. The SAR images exhibited a large variation of natural features produced by winds, internal waves, the bathymetric distribution, by convection, rain, etc as all of these produce variations in the sea surface roughness so that the topological changes may be studied and classified. In a similar way bathimetry may be studied with the methodology described here using the coastline and the thalwegs as generators of local vertical vorticity.
The advance of a Rayleigh-Taylor front is described in Linden & Redondo (1991),[1-3] and may be s... more The advance of a Rayleigh-Taylor front is described in Linden & Redondo (1991),[1-3] and may be shown to follow a quadratic law in time where the width of the growing region of instability depends on the local mixing efficiency of the different density fluids that accelerate against each other g is the acceleration and A is the Atwood number defined as the diference of densities divided by their sum. This results show the independence of the large amplitude structures on the initial conditions the width of the mixing region depends also on the intermittency of the turbulence. Then dimensional analysis may also depend on the relevant reduced acceleration driven time and the molecular reactive time akin to Damkholer number and the fractal structure of the contact zone [2,4]. Detailed experiments and simulations on RT and RM shock induced fronts analized with respect to structure functions are able to determine which mechanisms are most effective in local mixing which increase the effective fractal dimension, as well as the effect of higher order geometrical parameters, such as the structure functions, in non-homogeneous fluids (Mahjoub et al 1998)[5]. The structure of a Mixing blob shows a relatively sharp head with most of the mixing taking place at the sides due to what seems to be shear instability very similar to the Kelvin-Helmholtz instabilities, but with sideways accelerations. The formation of the blobs and spikes with their secondary instabilities produces a turbulent cascade, evident just after about 1 non-dimensional time unit, from a virtual time origin that takes into account the linear growth phase, as can be seen by the growth of the fractal dimension for different volume fractions. Two-dimensional cuts of the 3D flow also show that vortex flows have closed or spiral streamlines around their core. Examples of such flows can be also seen in the laboratory, for example at the interface of atwo-layer stratified fluid in a tank in which case streamlines are more regular. Mixing in turbulent flows remains less well understood, and in spite research some basic problems are still virtually unexplored.
Local Diffusion and the topological structure of vorticity and velocity fields is measured in the... more Local Diffusion and the topological structure of vorticity and velocity fields is measured in the transition from a homogeneous linearly stratified fluid to a cellular or layered structure by means of convective cooling and/or heating. Patterns arise by setting up a convective flow generated by an array of Thermoelectric devices (Peltier/Seebeck cells) these are controlled by thermal PID generating a buoyant heat flux. The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
Local Diffusion and the topological structure of vorticity and velocity fields is measured in the... more Local Diffusion and the topological structure of vorticity and velocity fields is measured in the transition from a homogeneous linearly stratified fluid to a cellular or layered structure by means of convective cooling and/or heating. Patterns arise by setting up a convective flow generated by an array of Thermoelectric devices (Peltier/Seebeck cells) these are controlled by thermal PID generating a buoyant heat flux. The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
Design and operation of thermoelectric coolers and heaters as well as the fluid mechanics of conv... more Design and operation of thermoelectric coolers and heaters as well as the fluid mechanics of convection is important [1]. We present a university-industrial colaboration that developed transient Thermoelectric driven convective models based on the control of thermal boundary conditions and flow measurements inside a closed enclosure for didactic uses. The coupling of heat transfer and electric conduction within semiconductors is important and takes into account all thermoelectric effects, including Joule and Seebeck heating, Thomson effect, Peltier effect and Fourier's heat conduction. We present a Thermoelectric driven heating and cooling experimental device in order to map the different transitions between two dimensional convection in an enclosure and the 3 D complex flows. The size of the box is of 0.2 x 0.2 x 0.1 m and the heat sources or sinks can be regulated both in power and sign [2,3]. The buoyancy driven flows are generated by Seebeck and Peltier effects in 4 to 40 wall positions. The parameter range of convective cell array varies strongly with the topology of the boundary conditions and buoyancy [4]. At present side and vertical heat fluxes are considered and estimated as a function of Rayleigh, Peclet and Nusselt numbers, but the tilting possibilities of the BEROTZA built experimental device also allow to heat/cool at any angle [5,6] (Redondo 1995, Redondo et al.2013). Fluid visualizations are performed by PIV, Particle tracking and shadowgraph/schliering [4]. Thermoelectric coolers offer the potential to better control and enhance the cooling of electronic modules to regulate operating temperatures or to allow higher power. Thermoelectric coolers are limited by the maximum heat fluxes and have lower coefficient of performance (COP) but offer a wide range of boundary fluid control. Environmental and Engineering Fluid Mechanics laboratories at university or professional schools may incorporate student practical work in several of many fields that need understanding such as:
Design and operation of thermoelectric coolers and heaters that may be used in detailled laborato... more Design and operation of thermoelectric coolers and heaters that may be used in detailled laboratory experiments of buoyancy driven trurbulence, as well as in the general fluid mechanics of convection is important, there seems to be a lack of comparison between numerical models of turbulent flows (Including Kinematic Simulation and DNS) and non-homogeneous experiments. [1-3] We present the results of a university-industrial colaboration that developed a Fluid Dynamic Didactic Apparatus able to model steady and transient Thermoelectric driven convective models based on the control of thermal boundary conditions and also optimized to perform flow measurements inside a closed enclosure. The Thermoelectric Convection Didactic Device (TCDD) presented here is basically designed for a range of didactic uses, but a wide range of innovative research options are available, both in the small 4x4 device shown in figure 1 and in larger and higher power equipments. We present here both the thermoelectric and the fluid flow description of the TCDD. The coupling of heat transfer and electric conduction within the semiconductor Thermal assemblies is important and takes into account the local thermoelectric effects, including Joule and Seebeck heating, Thomson effect, Peltier effect and Fouriers heat conduction. The macroscale heating cooling equations are presented together with the calibration and flow characteristics of the thermolectric convective devices shown only for an example configuration, but many other are possible.
Uploads
Books by Jackson Tellez
follow a quadratic law in time where the width of the growing region of instability depends on the local mixing
efficiency of the different density fluids that accelerate against each other g is the acceleration and A is the Atwood
number defined as the diference of densities divided by their sum.
This results show the independence of the large amplitude structures on the initial conditions the width of
the mixing region depends also on the intermittency of the turbulence. Then dimensional analysis may also depend
on the relevant reduced acceleration driven time and the molecular reactive time akin to Damkholer number and
the fractal structure of the contact zone [2,4].
Detailed experiments and simulations on RT and RM shock induced fronts analized with respect to structure
functions are able to determine which mechanisms are most effective in local mixing which increase the
effective fractal dimension, as well as the effect of higher order geometrical parameters, such as the structure
functions, in non-homogeneous fluids (Mahjoub et al 1998)[5].
The structure of a Mixing blob shows a relatively sharp head with most of the mixing taking place at the
sides due to what seems to be shear instability very similar to the Kelvin-Helmholtz instabilities, but with sideways
accelerations. The formation of the blobs and spikes with their secondary instabilities produces a turbulent
cascade, evident just after about 1 non-dimensional time unit, from a virtual time origin that takes into account the
linear growth phase, as can be seen by the growth of the fractal dimension for different volume fractions.
Two-dimensional cuts of the 3D flow also show that vortex flows have closed or spiral streamlines around
their core. Examples of such flows can be also seen in the laboratory, for example at the interface of atwo-layer
stratified fluid in a tank in which case streamlines are more regular. Mixing in turbulent flows remains less well
understood, and in spite research some basic problems are still virtually unexplored.
Papers by Jackson Tellez
The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
Teaching Documents by Jackson Tellez
Drafts by Jackson Tellez
follow a quadratic law in time where the width of the growing region of instability depends on the local mixing
efficiency of the different density fluids that accelerate against each other g is the acceleration and A is the Atwood
number defined as the diference of densities divided by their sum.
This results show the independence of the large amplitude structures on the initial conditions the width of
the mixing region depends also on the intermittency of the turbulence. Then dimensional analysis may also depend
on the relevant reduced acceleration driven time and the molecular reactive time akin to Damkholer number and
the fractal structure of the contact zone [2,4].
Detailed experiments and simulations on RT and RM shock induced fronts analized with respect to structure
functions are able to determine which mechanisms are most effective in local mixing which increase the
effective fractal dimension, as well as the effect of higher order geometrical parameters, such as the structure
functions, in non-homogeneous fluids (Mahjoub et al 1998)[5].
The structure of a Mixing blob shows a relatively sharp head with most of the mixing taking place at the
sides due to what seems to be shear instability very similar to the Kelvin-Helmholtz instabilities, but with sideways
accelerations. The formation of the blobs and spikes with their secondary instabilities produces a turbulent
cascade, evident just after about 1 non-dimensional time unit, from a virtual time origin that takes into account the
linear growth phase, as can be seen by the growth of the fractal dimension for different volume fractions.
Two-dimensional cuts of the 3D flow also show that vortex flows have closed or spiral streamlines around
their core. Examples of such flows can be also seen in the laboratory, for example at the interface of atwo-layer
stratified fluid in a tank in which case streamlines are more regular. Mixing in turbulent flows remains less well
understood, and in spite research some basic problems are still virtually unexplored.
The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows
The experiments described here investigate high Prandtl number mixing using brine and fresh water in order to form density interfaces and low Prandtl number mixing with temperature gradients. The set of dimensionless parameters define conditions of numeric and small scale laboratory modeling of environmental flows. Fields of velocity, density and their gradients were computed and visualized. When convective heating and cooling takes place the combination of internal waves and buoyant turbulence is much more complicated if the Rayleigh and Reynolds numbers are high in order to study mixing in complex flows