Recent content by casualguitar

I havent yet been able to work this out. Is this a dead end by any chance? I'm not 100% sure that it is the truncation error I should be considering. My apologies for all of the questions on this

Hi Chet, am I correct in saying - "If the truncation error on the advection term in the upwind scheme is the same as the dispersion term in the central differencing scheme (when l = delta x/2), then the numerical dispersion associated with the upwind scheme will be equal to the physical...

Hi Chet, my apologies please ignore the above as its not correct. I will revert later this morning on this

Thanks Chet. Have I identified this relationship correctly in my post #450 above?

We are comparing the numerical dispersion introduced by upwind differencing to the physical dispersion captured by the central differencing scheme. Given the energy balance: \begin{equation} \frac{d(\rho_x h_x)}{dt} = \frac{\phi_{x-\Delta x/2}(\frac{h_{x-\Delta x} + h_x}{2})- \phi_{x+\Delta...

Hi Chet, is the claim that the numerical dispersion from the upwind scheme is exactly the same as the physical dispersion in the central differencing scheme, or is the claim only that they are of the same order of magnitude?

Hi Chet, my apologies yes I have effectively completed thesis writing at this point, I was more curious about future work on this than anything. I did have one question on the modelling of physical dispersion using numerical dispersion (I was hoping to flesh this out a small bit more as it is...

Hi Chet, I hope you're doing well. I see you're very active here lately which is great (really is a god send for postgraduate students). I wanted to respond to the above comment from you. There now exists an experimental setup that will allow for the measurement of axial temperature profiles in...

Hi Chet, in your view is the above approach reasonable? This would mean that I am not tuning to any liquid phase temperature profiles, but instead tuning this two phase model to gas phase temperature profiles only (of which there is lots of data), and also showing that the dispersion...

4) in the case that we do get a match (with the Carberry et al liquid and gas phase dispersion coefficients above), we can make the claim that our dispersion length of ##0.03m## is suitable for both liquid and gas phase in the range of velocities simulated

Hi Chet, I think I found something relevant in section 8.30 "Miscible Displacement in Porous Media", Figure 8.2 linked here:848448 Would it be reasonable to make the case that the dispersion coefficient is not a strong function of phase but velocity? If so, I could: 1) take the range of...

Thanks Chet. Something like this (going from 0.1 to 10)? If you mean calculate an ##\frac{l_h}{d_p}## value for their data, then I calculated this as being equal to about 1.33 which is inside our range of 1.2 - 2.4. I can post this calculation if necessary. So from the above we can possibly...

To check this assumption for the CO2 model, we did something like the plot below: If suitable, I will redo this calculation for this system and run for a range of Re values. It seems like we will at least get an Re 'range of validity' for the ##\Delta x = 2l## assumption, and won't have to...

Sorry yes my mistake I suppose there is no "comparing upwind and central differencing schemes", because only have central differencing. I am saying this, but we may have already done this unless I'm misunderstanding. We calculated ##l## with that Ruthven et al correlation, where ##l## is a...

Hi Chet, back on this. In terms of looking further into this "modelling numerical dispersion as physical dispersion" observation, there seems to be a few options for progression. 1. Check if this happens for other equations in other domains in an equivalent sense 2. Consider the observation for...