Matlab - importing data from excel & interpolating

[DyslexicHobo]

I have data that I'm using for a wind turbine project. The project requires that I retrieve data from an excel sheet that was supplied of experimentally tested values for lift and drag. These values for lift and drag are based on a value alpha (an angle, but irrelevant to the coding question).

Right now, I have used Excel's line of best fit approximation (using a 6th degree polynomial) along with different if statements to get the values, but I've found that there can be up to 30% error in some calculations. Instead, I'd like to import the data to excel and use Matlab's interpolate function to find these values.

The only problem is... I have no clue how to go about importing the data to excel or how to use the interpolate function. My Matlab experience is literally non-existent. I have minor experience in Java but that's it.

What's the easiest way to import the data from excel, and what functions can I use to interpolate the data? Thanks!

Here's the code I'm trying to replace:

            %FINDING CL
            if(alpha>0 && alpha <= 8)
                Cl = -0.0001*alpha^5 + 0.0016*alpha^4 - 0.0093*alpha^3 + 0.0219*alpha^2 + 0.0928*alpha + 0.0006;
            elseif(alpha > 8 && alpha <= 27)
                Cl = -.00001*alpha^2 + 0.0542*alpha - 0.5037;
            elseif(alpha > 27 && alpha <= 90)
                Cl = -.00000009*alpha^4 + .00003*alpha^3 - 0.0036*alpha^2 + 0.1761*alpha - 1.8521;
            else
                Cl=0;
            end

            %FINDING CD
            if(alpha >= 0 && alpha <= 8)
                Cd = -.00001*alpha^3 + 0.0003*alpha^2 - 0.0003*alpha + 0.0134;
            elseif(alpha > 8 && alpha <= 90)
                Cd = -.0000000004*alpha^5 + .0000002*alpha^4 - .00003*alpha^3 + 0.0018*alpha^2 - 0.0196*alpha + 0.1616;
            else
                Cd = 0;
            end

 

[shoehorn]

What's the easiest way to import the data from excel,

Locate your data file in Matlab's 'Current Directory' window. Right-click on the file and select 'Import Data'. The use the GUI to import the data into matlab.

and what functions can I use to interpolate the data? Thanks!

Matlab's documentation discusses interpolation and fitting at great length. Use the help browser to search for 'Interpolation'.