Flow around a cylinder and vortices

[Espec]

Hello everyone, I am quite struggling with a question that I received on a problem sheet. I have looked information regarding to this but I still have a hard time visualizing this and sketching it.

Homework Statement

In the question I am asked to describe using a sketch how flow separation from the cylinder may be simulated by the addition of isolated vortices and explain how vortices can be used to complete the flow. In a separate point it asks again on a sketch to show how the separation points affect the drag component of force.

Homework Equations

Unfortunately I unsure as how to proceed in this situation.

The Attempt at a Solution

My attempt at a solution revolved around using the Method if images but so far I have not been able to reach a solution.Any assistance or indication to the relevant literature to this exercise would be much appreciated. I am new to this site and still familiarizing myself with the rules and FAQ, if I have broken any of them I apologize.

Thank you for your help on this matter.

 

[KataKoniK]

Thank you for reaching out for assistance with your question. Flow separation from a cylinder can be a complex phenomenon to visualize, but there are some ways to simulate it using vortices.

First, let's define what vortices are. They are regions of swirling motion in a fluid, which can be created by various means such as obstacles in the flow or differences in fluid velocity. In the case of flow separation from a cylinder, vortices can be used to mimic the flow patterns that occur when the fluid separates from the surface of the cylinder.

To simulate flow separation using vortices, you can start by placing a vortex on either side of the cylinder, near the point where separation is expected to occur. This will create a swirling motion in the fluid, similar to what happens when the flow separates from the cylinder. By adding more vortices along the cylinder's surface, you can create a more accurate simulation of the separation pattern.

Now, how do vortices help complete the flow? Vortices can actually help to reattach the separated flow back to the surface of the cylinder. By strategically placing vortices along the separation points, the swirling motion can redirect the flow back towards the surface, thus reducing the drag force on the cylinder.

As for the sketch showing how the separation points affect the drag component of force, you can draw a graph with the drag force on the y-axis and the distance along the cylinder's surface on the x-axis. The separation points will create peaks in the graph, indicating a higher drag force at those points. By using vortices to reattach the flow, you can show how the peaks decrease and the overall drag force is reduced.

I hope this explanation helps you in your problem-solving process. As for relevant literature, I suggest looking into the concept of vortex shedding and its applications in fluid dynamics. Good luck with your problem sheet!