# FLUID MECHANICS

 The science concerned with fluids, either at rest or in motion, and dealing with pressures, velocities, and accelerations in the fluid, including fluid deformation and compression or expansion.

## Related Terms

### PLASTICOVISCOSITY

Plasticity in which the rate of deformation of a body subjected to stresses greater than the yield stress is a linear function of the stress.

### PLASTIC COLLISION

A collision in which one or both of the colliding bodies suffers plastic deformation and mechanical energy is dissipated.

### PERMANENT SET

Permanent plastic deformation of a structure or a test piece after removal of the applied load. Also known as set.

### MUSKHELISHVILI'S METHOD

A method of solving problems concerning the elastic deformation of a planar body that involves using methods from the theory of functions of a complex variable to calculate analytic functions which determine the plane strain of the body.

### MOIRE INTERFEROMETRY

An optical technique that measures the components of deformation of a specimen surface in the plane of the surface by superposing a reference grating and a diffraction grating that is applied to, and deforms with, the surface.

### MODULUS OF ELASTICITY IN SHEAR

A measure of a material's resistance to shearing stress, equal to the shearing stress divided by the resultant angle of deformation expressed in radians. Also known as coefficient of rigidity; modulus of rigidity; rigidity modulus; shear modulus.

### MAGNETOSTRICTIVE LOUDSPEAKER

[ENG ACOUS] Loudspeaker in which the mechanical forces result from the deformation of a material having magnetostrictive properties.

### KELVIN BODY

An ideal body whose shearing (tangential) stress is the sum of a term proportional to its deformation and a term proportional to the rate of change of its deformation with time. Also known as Voigt body.

### INELASTIC

Not capable of sustaining a deformation without permanent change in size or shape.

### HOOKEAN DEFORMATION

Deformation of a substance which is proportional to the force applied to it.

### Related questions

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