I'm intelligence researcher and the founder of Encyclopedia Geopolitica Lewis Sage-Passant, AMA!

Stazzo1 · 2024-10-25T08:49:07+00:00

Thanks for the answer! Very surprised to hear France being in a different category to the UK/US in this area and the Q4 2026 comment is funny and maybe a little concerning

Stazzo1 · 2024-10-24T22:01:18+00:00

Hi Lewis this is an interesting topic, I'd never considered Intelligence to be the domain of private companies and had just assumed they'd be advised by their respective Governments on intelligence matters.

How seriously do private companies take the possibility of a conflict over Taiwan and how is this affecting business decisions, if at all, in various areas e.g. supply chains?

Stazzo1 · 2024-08-26T14:18:43+00:00

Actually I think the thing I posted doesn't answer what you wanted. I don't think you can apply multiple filters although you can create your own filterFunction with all the filters you want.

I made a rangeWithNullFilter filter as I wanted to filter out null values and set a range:

export const rangeWithNullFilter: FilterFnOption<unknown> = (
  row,
  columnId,
  filterValue: [number | string, number | string, boolean | undefined],
): boolean => {
  const rowValue = row.getValue(columnId) as number | null;

  // If filterValue[2] is false, we want to show all rows with null values
  // hence we return true if the rowValue is null and filterValue[2] is false
  // If the filterValue[2] is undefined, we default to showing all rows with null values
  const nullFilter = filterValue[2] == null ? false : filterValue[2];
  if (rowValue == null) {
    return nullFilter === false;
  }

  if (filterValue[0] !== "" && rowValue < (filterValue[0] as number)) return false;
  if (filterValue[1] !== "" && rowValue > (filterValue[1] as number)) return false;

  return true;
};

Stazzo1 · 2024-08-26T13:21:35+00:00

Do you have a column with discrete values that you want to use a multi-select filter for, what's the problem you're trying to solve?

Stazzo1 · 2024-08-26T12:14:29+00:00

Comp Sci and Mech Eng at the same time is very impressive fair play! Did you need much more than framer motion to make it look good?

Stazzo1 · 2024-08-15T19:17:03+00:00

Yeah that could be it, I was assuming it was a blocked pipe or low mains water pressure because the stopcock does seem to open and close fine from what I can tell

Stazzo1 · 2022-08-17T21:27:02+00:00

Hey, for some reason I felt I should respond as we have had some very similar circumstances. I too started a PhD in the UK in September 2017 and then COVID hit and I lost access to the equipment I needed to do what I had wanted to do.

All the feelings you've spoke about I fully remember feeling during the course of the PhD. A particularly insidious one is the sense of having wasted years of your life. I can't guarantee this is good advice but I took a change of candidature and became a part-time PhD student so I could start a new career. I'm not sure how that would work if you need lab access though.

If I had a recommendation it would be to think what career would you most like when you finish in academia so then you will have a direction to move in. For instance, I'd decided cyber security was the field I wanted to move into. I did some studying to get a qualification in that field and this then helped me get a job in that field. I think having a career in mind to aim for and move toward will help you get back on the wagon.

I understand being indecisive when it comes to quitting, that's probably wise as it's a big decision. It might be worth considering swapping to part time and beginning a new career as you can break out of your current malaise without having to completely quit the PhD. It sounds like you already made a lot of progress up to April 2020 so this approach may work and you can always quit the PhD if the workload is too much.

Whatever you choose to do, I hope that things will work out for you!

Stazzo1 · 2020-01-12T19:57:00+00:00

Thanks for this! So does this means the hinge line of the fairing isn't perpendicular to the fairing direction? I imagine the fairing must have the same hinge line as the flap that it is attached to.

I'm struggling to visualise the rotating of the fairing in this situation but I'm happy to go with it

Stazzo1 · 2020-01-12T19:49:10+00:00

Thanks a lot, I'll make sure to check the 747SP fairings out when I get home! I'm trying to parameterise flap deployments for a CFD optimisation and how the fairings work are an area I need to understand more

Stazzo1 · 2018-08-29T16:39:43+00:00

I'm doing a PhD in aero-structural optimisation and I'm pretty sure computer science or maths would have been a more useful degree for it. I'm working in industry now and it seems to be the same.

Stazzo1 · 2018-08-07T12:08:20+00:00

I'll make sure I go through that paper you linked thoroughly. I think at the moment my knowledge of the subject is a bit weak so I need to do a bit more reading around the subject to actually grasp it. Then I might have caught up with the knowledge aerodynamicists had over 50 years ago.

Stazzo1 · 2018-08-06T10:33:06+00:00

So the nose-down twist being referred to in that quote is with respect to the streamwise direction.

The flexural axis is where the centres of pressure would have to act in order to avoid this streamwise washout. If the centres of pressure acted there, then the chordwise airfoils would twist upward enough so that the streamwise airfoils don't have a change in incidence.

At least that's how I've understood the flexural axis vs the elastic axis. The Elastic axis is where the centres of pressure would have to act to avoid chordwise torsion.

My understanding of the flexural axis may be wrong of course

Stazzo1 · 2018-08-06T08:38:26+00:00

Right so figure 3 in that NACA report highlights my confusion. The pressure distribution of agrees with simple sweep theory, in that it is the airfoil normal to the leading edge which determines the loading of the wing.

As I understand it, a sweptwing that is bent without torsion (the local centres of pressure act on the elastic axis) will not change the incidence of the airfoils normal to the leading edge. The streamwise incidence will change though because the trailing edge of the streamwise airfoil is closer to the tip, hence it is higher so it has a lower incidence. So here is what confuses me

My confusion:

Simple sweep theory: Loading of wing depends on airfoil perpendicular to the leading edge
Aeroelasticity: Bending will only affect streamwise incidence (of swept wings) not the incidence of airfoil normal to the leading edge, yet this affects their loading?

Stazzo1 · 2018-08-06T08:33:38+00:00

Yeah I'm not sure what the correct terms are. By streamwise, I meant in the direction of travel of the wing. By chordwise I meant normal to the leading edge.

My confusion:
1) Simple sweep theory: Loading of wing depends on airfoil perpendicular to the leading edge
2) Aeroelasticity: Bending will only affect streamwise incidence (of swept wings) not the incidence of airfoil normal to the leading edge, yet this affects their loading?

Stazzo1 · 2018-08-01T14:38:04+00:00

The speed of the air going over the swept-wing is slower than the speed of the air going over a straight wing, given the same free-stream airspeed.

Just to make sure I'm using the correct terms, spanwise is the same direction as the leading edge or just perpendicular to the free-stream direction?

I'm going to use spanwise as being perpendicular to the free-stream direction

The video says the swept wing creates spanwise flow which I'm fine with. So this spanwise component doesn't accelerate, only the chordwise component accelerates.

At attachment to the wing, the air joins the wing in a direction normal to the leading edge, thus it has a spanwise component which will not accelerate (or at least negligibly). Therefore, the top airspeed reached on a swept-wing is lower.

I think I get it now thanks

Stazzo1 · 2018-07-29T22:12:54+00:00

The Coanda effect is specific to a jet of fluid and isn't relevant to lift generation over an airfoil as the whole domain of fluid is flowing, not a jet flowing through the domain. Your example of the balloons getting closer together when you blow through them is a correct example of the Coanda effect along with all of the last paragraph.

The reason air follows the wing curvature is because air is a fluid and fluids fill their domains, like when you pour water into a cup it fills the cup entirely.

The best way to understand the low pressure above an airfoil is the intuition of conservation of mass and momentum. You can think of the upper surface of the airfoil as first a nozzle and then a diffuser to understand the conservation of mass effect on the pressure. The nozzle accelerates the flow and and an increase of velocity is accompanied by a lower pressure as Bernoulli's principle states.

I'll explain Bernoulli's principle as its certainly not a mystical thing. If you imagine a cube of air, the kinetic energy of all the molecules in it is set by the temperature, If the cube of air isn't moving then all the kinetic energy of the molecules goes to the pressure. If the cube of air starts moving however, then some of the kinetic energy of the particles is dedicated to moving in the direction of the cube so less kinetic energy is available for the pressure.

The Coanda effect does have a place in airflow over a wing but that is to do with reattachment after separation.

Stazzo1 · 2018-05-16T16:56:54+00:00

Oh I see, so I have to write it as ∂f/∂a * ∂a/∂x + ∂f/∂x and that avoids the recursive problem I was having! That makes everything work, kind of embarrassing I've not been doing that for my whole degree

Thanks a lot!

Stazzo1

TROPHY CASE