7.1 Scalars and Vectors
Scalar Quantities. There are two types of quantities describing fluid flows: scalar and vector quantities. Scalar quantities are quantities that are described only by a magnitude. They do not have a direction of action. For fluids the relevant scalar quantities are
• temperature T , measured in K
• density ρ, measured in kg m− 3
• pressure p, measured in Pa
In the following we will use the symbol ψ whenever referring to a scalar quantity.
Vector Quantities. Vector quantities have both magnitude and a direction of action. The relevant vector quantities of fluid flows are
• position , measured in m
• velocity , measured in m s− 1
• acceleration , measured in m s− 2
In the ...