So why do big metal ships float, anyways?

[Pulsar]

He is 100% correct. The reason why there is a pressure difference is a whole different story. The trick is producing large amounts of lift with low drag. I am an aerodynamicist and I guarantee you've flown on airplanes I've helped design.

Boats, on the other hand, still need helium or mermaids.

If you are actually an aerodynamicist, and believe that the statement 'because air travels more quickly over the top of the wing than under" is the root cause of why a plane flies then I'm worried about any plane you've designed.

 

[KillerCharlie]

If you are actually an aerodynamicist, and believe that the statement 'because air travels more quickly over the top of the wing than under" is the root cause of why a plane flies then I'm worried about any plane you've designed.

You can continually ask "why" a million times for anything and never arrive at the true root cause. His initial response was perfectly accurate for one those levels of "why."

Why is there a velocity/pressure difference on a wing with camber or flying at an angle? Because viscosity generally forces the flow to join smoothly near the trailing edge. Without viscosity, lift is not produced (in incompressible flow). In fact, in inviscid CFD codes (potential, Euler), lift is not produced unless without either the Kutta condition (derived from physical observation) or numerical/artificial viscosity. Why does viscosity exist? I don't care, I don't need to keep asking "why" anymore because at that point I have what I need to modify aerodynamic characteristics.

I have a little bit experience. If you've ever flown commercially, then you've been on an airplane that I've worked on the aerodynamics for in some form. I've been on 10+ wind tunnel tests in 3 states and 3 different countries. I run CFD codes nearly every day on large computer clusters with several hundred processors. I've been asked by other companies to evaluate and verify their aerodynamic designs. I've designed many cruise wings that were tested, including wings that have gone into production. I've designed high-lift systems and then been on the flight tests demonstrating stall performance and handling characteristics. It is one thing to design part of an airplane, but it's an entirely different thing to place your life in the hands of that design when it's tested for the first time.

A lot of people think they know aerodynamics, but very very few of them have had the privileges I've had in working on this kind of stuff.

 

[JulesMaximus]

Ships weigh less than a duck.

Then it must be made of wood! Burn it!

 

[IronWing]

Subs are made of titanium. Titanium is used to make white paint. So why are subs black?

 

[pcgeek11]

Subs are made of titanium. Titanium is used to make white paint. So why are subs black?

Some Russian subs are. US Submarines are made from steel ( HY80 Steel ).

https://en.wikipedia.org/wiki/HY-80

 

[sdifox]

Subs are made of titanium. Titanium is used to make white paint. So why are subs black?

Titanium so White

 

[mxnerd]

But why should I or anybody be serious about any question asked by OP?

 

[DigDog]

displacement of water.

the weight of the ship pushes down, and moves a large amount of water out of the way. water isn't happy about this, and pushes back to go where the boat is, thus pushing the boat back up.

 

[dave_the_nerd]

Subs are made of titanium. Titanium is used to make white paint. So why are subs black?

Titanium Oxide is white. Actual Titanium is fuschia, but the USN thought that looked weird, so they paint their submarines black so they can blend in with the whales.

 

[foghorn67]

That is incorrect.

Sure, you can have flight without that, but why would you want that?

 

[pcgeek11]

Titanium Oxide is white. Actual Titanium is fuschia, but the USN thought that looked weird, so they paint their submarines black so they can blend in with the whales.

USN Subs are made of HY-80 steel.

 

[dave_the_nerd]

USN Subs are made of HY-80 steel.

Sometimes I doubt your commitment to Sparklemotion.