why pipes are cylindrical ?

this is jst a simple one... pipes are mostly cylindrical in shape... why cant they be in square or triangle in shape.. i know cylindrical shapes hold pressure more than that of any edge shape things... are there any other reasons... are there reasons concerned with flow??

equation of continuity holds good in cylindrical pipes and moreover they occupy less space when compared to square or rectangular shaped ones

another reason : They fit in other shape like square .

Plz read some book before typing in here!!

Equation of continuity holds true for the following case:
Irrotational, stream-line flow of an incompressible and non-viscous fluid

here shape and size of da vessel doesnt matter!

@ thread starter
Plz go through the topic of PRESSURE VESSELS ,regarding STRNGTH of MATERIALs , in books written in Johnston & Bearson...u will get ur answer!
no offense, check out your understanding for the sentence you typed


stream-line flow of an incompressible and non-viscous fluid
When water is flowing through the pipe, there is an internal pressure. With a circular shape, the pressure force is evenly distributed around the entire circumference of the pipe. With squares, triangles, or any other shape with sharp corners, the pressure forces concentrate at these locations. Therefore, the edges or corners would have to be reinforced, adding weight to the pipe and increasing the complexity of manufacturing.

Shape and size doesnt matter for the equation of continuity to hold true..!!

but as far as the question goes....shape does matter for the uniform distribution of force..!!..and bridge a suitable relation between lateral and logitudinal strain.

Since a basic objective for an engineer wud b to check out , the stability of the material.

area to circumference ratio is the right answer.
not only this, the liquid flow rate can be measured easily.
it has something to do with bending moment also. cylindrical pipes can be bend easily in a curved path as compared to any other shape.

Cylindrical shapes hold more internal pressure than that of edged objects, where it concentrates.... i agree with that, but do the rate of flow vary??

I am saying, in case of cylindrical pipes, it becomes easier to measure flow rate..
The spinner is placed in the center. the velocity gradient is parabolic and velocity of fluid is maximum at center. it can be calibrated with spinner RPM verses flow rate.

... given a N sided polygon ( perimeter is fixed ) .. to maximise the area it shd be regular polygon ..
now of all regular polygons of given perimeter CIRCLE HAS THE LARGEST AREA...
now stretch all regular 2-d polygons to get infinite or finite pipes ... now using above results or othws we can prove dat OF ALL SUCH PIPES WITH GIVEN LATERAL SURFACE AREA CYLINDER HAS THE MAXIMUM VOLUME ... now it means dat if v r provided with given area of sheet to maximize the volume of water flow per unit time we will convert it into a cylinder