Using LINEST for Least Squares Regression With More Than One Independent Variable

The use of least squares regression and curve fitting is well established in the applied sciences. It is discussed in detail in the monograph Least Squares Analysis and Curve Fitting. Most analyses of this type, however, are done with only one independent variable (the classic linear fit is a good example of this.)

For some problems it is necessary to consider two or more independent variables (a recent example is here.) A way to perform regression on such data is to use the LINEST function, which can be used for linear/planar types of correlations. It can be found in most of the current spreadsheet packages. It is tricky to use; about the only way to illustrate its use is through a video, and one from Dr. Todd Grande is featured here.

Fluid Mechanics Laboratory Video: Flow Meters, Gate Valve and Pipe Losses (Moody Chart)

Our main fluid mechanics laboratory page is here.  Other resources relating to this laboratory is here:

Chauvenet’s Criterion

In the pressure gauge testing lab experiment, one of the requirements is that the “outliers” in the data are determined and excised from the analysis. One way of doing that is to apply Chauvenet’s Criterion. Below is a video of how that’s done and who Chauvenet was.

Note: he butchers the pronunciation of Chauvenet, sorry.

Flexible Meshing Enables Accurate CFD for Nuclear Reactor Rod Bundles — Another Fine Mesh

Accurate fluid flow modeling of nuclear reactor rod bundles is essential and extremely challenging with exacting standards for the mesh to deal with the geometric complexity and near-wall physics. The tightly packed rods with wrapped wires, mainly used in liquid metal cooled systems, that contact the rods provide a challenging geometry into which well-defined boundary […]

via Flexible Meshing Enables Accurate CFD for Nuclear Reactor Rod Bundles — Another Fine Mesh

The Physics of River Prediction

From here, beginning follows:

Rivers support life and fuel civilization. They provide water for drinking, irrigate food crops, and help build everything from cars to computers. Their waters drive hydroelectric turbines that generate clean energy. Rivers have even supported nuclear physics developments that changed the course of a war: The hydroelectric complexes of the Columbia Basin Project and the Tennessee Valley Authority enabled energy-intensive uranium and plutonium refinement for the Manhattan Project.

Rivers have always been crucial transportation pathways. The exploration, settlement, and economic development of the Americas depended acutely on river navigation. The Danube serves as a trade route in Europe, much as it did for the Romans 2000 years ago, and today it carries commercial freight across the continent….