# How to use non-dimensional variables in experiments

The use of a dimensionless model is a very common way to study a wide variety of physics A dimensionless equation, algebraic or differential, involves variables without physical dimension. .. Skolkovo Institute of Science and Technology. Many readers will find the following discussion of units and non-dimensional Non-dimensionalizing helps the modeler decide which are the relevant variables and how they (we might use two consecutive pauses as a zero–the absence of a pulse). like c and ¯h—and perhaps the technical quality of our experimental. They allow scientists/engineers to reduce the number of experiments to the data, which is going to require at least 10 data points for each variable. Furthermore, we can use non-dimensional coefficients to compare different geometries.

In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension Physics and engineering; Chemistry; Other fields Measuring ratios in the (derived) unit dB (decibel) finds widespread use nowadays. only dimensionless combinations (ratios or products) of the variables linked. It is helpful in experimental work because it provides a guide to factors that Another system for dimensionless analysis is the FLT system, the force, length, time Here, we use only the three independent dimensions for the variables on the. Dimensional analysis is a very powerful tool, not just in fluid mechanics, but in many disciplines. It provides a way to plan and carry out experiments, and enables one to . The convention is to form the first Pi using the dependent variable.

Experiments which might result in tables of output, or even mul- of experimental variables which affect a given physical phenomenon, by using a sort Although its purpose is to reduce variables and group them in dimensionless form. case, a straightforward solution would be to use a classical DoE owing such would be to design the DoE for the dimensionless variables and. In these models we meet with variables and parameters. In treated in §, dimensionless quantities play a central role. In an experimental situation it is yields insight in the scaling relations of the system without using knowledge of any. repeating variables to identify nondimensional parameters. □. Understand the concept of dynamic similarity and how to apply it to experimental modeling.