Hydrostatic Forces in Layered Fluids
All of the above results which employ the linear hydrostatic variation of pressure are valid only for
homogeneous ?uids. If the ?uid is heterogeneous, consisting of individual layers each of constant
ysesldensity, then the pressure varies linearly with a different slope in each layer and the preceding ana
.must be remedied by computing and summing the separate contributions to the forces and moments
The same principles used above to compute hydrostatic forces can be used to calculate the net pressure
force acting on completely submerged or ?oating bodies. These laws of buoyancy, the principles of
Archimedes, are that:
1. A completely submerged body experiences a vertical upward force equal to the weight of the
displaced ?uid; and
2. A ?oating or partially submerged body displaces its own weight in the ?uid in which it ?oats
(i.e., the vertical upward force is equal to the body weight).
The line of action of the buoyancy force in both (1) and (2) passes through the centroid of the displaced
volume of ?uid; this point is called the center of buoyancy. (This point need not correspond to the center
of mass of the body, which could have nonuniform density. In the above it has been assumed that the
displaced ?uid has a constant g. If this is not the case, such as in a layered ?uid, the magnitude of the
buoyant force is still equal to the weight of the displaced ?uid, but the line of action of this force passes
through the center of gravity of the displaced volume, not the centroid.)
If a body has a weight exactly equal to that of the volume of ?uid it displaces, it is said to be neutrally
buoyant and will remain at rest at any point where it is immersed in a (homogeneous) ?uid.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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