#### Presentation Title

Creating Linearly Stratified Density Gradients In the Lab for Geophysical Studies

#### Faculty Mentor

Michael Burin

#### Start Date

17-11-2018 12:30 PM

#### End Date

17-11-2018 2:30 PM

#### Location

CREVELING 75

#### Session

POSTER 2

#### Type of Presentation

Poster

#### Subject Area

physical_mathematical_sciences

#### Abstract

Geophysical fluid dynamics are influenced by both the stratification of the fluid and the rotation the system is under. Because these are a major factor in meteorological events, there is great interest in understanding and modeling these phenomena. To better understand the effects of stratification we have constructed our own version of the “double tank” method for generating linear density gradients. A linear density gradient is a change in density that is directly proportional to height or depth. This is also a form of stratification. Being able to execute this technique reliably is essential because linear density gradients describe many systems we see in nature, both atmospheric and oceanic. The goal was to be able to reliably create stratified mixtures that can then be used to design small-scale models and conduct experiments to better understand their effects on fluid motion. The double tank method was originally developed in the 1960s and it involves mixing fluids between two tanks, then pumping the final mixture into a third tank that will have the desired density gradient. It has since been refined for efficiency and expanded upon to construct arbitrary density gradients. The version we created is strictly focused on linear gradients. We used water with increasing salinity to represent the increase in density. The salinity can be measured via the conductivity at different depths. This is will serve as a model of oceanic systems where the salinity is not uniform but rather stratified, similar to the upper ocean. After measuring the change in conductivity and evaluating the corresponding change in density, we determined we were successful in creating the density gradient. In the future we hope to combine our double tank method with a Taylor-Couette device to see the effects of placing the fluid in a rotating system.

Creating Linearly Stratified Density Gradients In the Lab for Geophysical Studies

CREVELING 75

Geophysical fluid dynamics are influenced by both the stratification of the fluid and the rotation the system is under. Because these are a major factor in meteorological events, there is great interest in understanding and modeling these phenomena. To better understand the effects of stratification we have constructed our own version of the “double tank” method for generating linear density gradients. A linear density gradient is a change in density that is directly proportional to height or depth. This is also a form of stratification. Being able to execute this technique reliably is essential because linear density gradients describe many systems we see in nature, both atmospheric and oceanic. The goal was to be able to reliably create stratified mixtures that can then be used to design small-scale models and conduct experiments to better understand their effects on fluid motion. The double tank method was originally developed in the 1960s and it involves mixing fluids between two tanks, then pumping the final mixture into a third tank that will have the desired density gradient. It has since been refined for efficiency and expanded upon to construct arbitrary density gradients. The version we created is strictly focused on linear gradients. We used water with increasing salinity to represent the increase in density. The salinity can be measured via the conductivity at different depths. This is will serve as a model of oceanic systems where the salinity is not uniform but rather stratified, similar to the upper ocean. After measuring the change in conductivity and evaluating the corresponding change in density, we determined we were successful in creating the density gradient. In the future we hope to combine our double tank method with a Taylor-Couette device to see the effects of placing the fluid in a rotating system.