KNOW WHY LIQUID CARRYING TRUCKS HAVE ELLIPTICAL TANKS !!

Many kinds of liquids are transported by road and railway. The tanks carrying these liquids are made cylindrical in shape and not cubical. Why is this so?  If tanks are made in cube or cuboid, the capacity of the tanks will increase and they can hold more cargo. Even the large tanks used in refineries for holding the petroleum products are cylindrical in shape.

Let's check out the answer:

1.)No stress concentration

A cylindrical container doesn’t have ‘weak spots’ that need reinforcing, which would translate to using more material to build the tanker. In contrast, a rectangle/square has corners and flat sides, which create weak points for pressure. In other words, a rectangle-shaped container would fail faster than a cylindrical one upon experiencing a great deal of pressure.

2.)Stability

The stability of the vehicle, especially one carrying liquids like oils and liquefied flammable gases, is of paramount importance. As such, you want to choose a shape whose center of gravity is as close to the ground as possible. Rectangles and squares are poor choices in this regard, as the center of gravity of a rectangular tanker would be at a greater height than that of a cylindrical tanker.Cylindrical tankers offer a low center of gravity, which is good news for the stability of the truck. 

3.)Liquid extraction and maintenance

A cylinder, as you can imagine, is more favorable when it comes to extracting the liquid contents of the tanker, as it lets the liquid funnel down to the bottom of the tank.A rectangle, on other hand, wouldn’t be a great choice in this regard. This is the same reason why most bathroom sinks are NOT rectangular.