Fluid Dynamics: Flame front in a channel

In summary, to find the velocity distribution in the channel, we need to use the continuity equation and the momentum equation, taking into account the non-slip boundary conditions and the pressure gradient caused by flame acceleration.
  • #1
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A flame front accelerates exponentially in a channel of width 2R with non-slip boundary conditions at the walls. Flame acceleration creates pressure gradient -deltaP/density=exp(sigma*t) (x-direction) directed parallel to the channel walls.

Assuming a plane-parallel flow, find velocity distribution in the channel.

I started with the Navier-Stokes equation and because of the plane-parallel flow and pressure gradient I came to this equation:

du/dt=exp(sigma*t)+my*du2/dy2

But now I don't know how I will continue, someone has an idea? Maybe I'm on the wrong track?

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  • #2
The Navier-Stokes equation is not applicable for this problem because it does not take into account the boundary conditions. Instead, we need to use the continuity equation and the momentum equation.The continuity equation states that the flux of mass through any area of a fluid must remain constant, so we can use this to calculate the velocity distribution in the channel. The momentum equation takes into account the pressure gradient and the non-slip boundary conditions to solve for the velocity profile. The velocity distribution in the channel can be found by solving the following equations: Continuity equation: ∂u/∂t + ∂(uv)/∂x = 0 Momentum equation: ρ(∂u/∂t) + ρ(u∂u/∂x) + ∂P/∂x = μ (∂2u/∂y2) where u is the velocity in the x-direction, v is the velocity in the y-direction, P is the pressure, Ρ is the density and μ is the dynamic viscosity. By solving these equations with the given boundary conditions, we can find the velocity distribution in the channel.
 

Related to Fluid Dynamics: Flame front in a channel

1. What is fluid dynamics?

Fluid dynamics is a branch of physics that deals with the study of how fluids, such as liquids and gases, move and behave under different conditions. It involves the study of fluid properties, motion, and forces, and is used to understand and predict the behavior of fluids in various systems.

2. What is a flame front?

A flame front is the leading edge of a flame as it propagates through a fuel-air mixture. It is characterized by a sharp boundary between the unburned and burned regions of the mixture.

3. How does a flame front behave in a channel?

In a channel, a flame front can propagate in different ways depending on the fluid dynamics of the system. It can either spread uniformly along the channel, or it can become unstable and create flame patterns, such as wrinkles or fingers, due to turbulent flow and instabilities in the fluid.

4. What factors affect the behavior of a flame front in a channel?

The behavior of a flame front in a channel is influenced by several factors, including the properties of the fuel and oxidizer, the geometry of the channel, the flow rate of the fluid, and the presence of any obstacles or walls that can affect the fluid flow.

5. Why is studying flame front behavior important?

Understanding the behavior of a flame front in a channel is crucial in many practical applications, such as combustion engines, industrial processes, and fire safety. By studying the fluid dynamics of a flame front, scientists and engineers can design more efficient and safe systems and predict the behavior of fires in different environments.

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