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--- home_server:mswindows_notes [2024-02-25 Sun wk08 12:08] – [friction factor calculation] baumkp
+++ home_server:mswindows_notes [2024-04-05 Fri wk14 05:38] (current) – [Excel Conditional Formatting Applies to Field Changing Unexpectedly] baumkp
@@ Line 237: / Line 237: @@
 ====friction factor calculation====
 Earlier in my engineering career I used Lotus123 and MSExcel with iteration to calculate the friction factor of piping with Newtonian fluid according to the [[https://en.wikipedia.org/wiki/Darcy_friction_factor_formulae#Colebrook%E2%80%93White_equation|Darcy friction factor formulae]].  To remove the iteration from the spreadsheet I wrote a simple VB script that took care of this.  When I get the change I will copy the script here.
-<code>
+++++VSBasic code for Colebrook Equation|
-</code>
+<code basic>'Public Re As Double 'Reynold number unitless 0<Re<10E9
-As can be seen in the wiki page, [[https://en.wikipedia.org/wiki/Darcy_friction_factor_formulae#Colebrook%E2%80%93White_equation|Darcy friction factor formulae]],
+'Public Rr As Double 'Relative Roughness unitless
+Public Ff As Double 'Friction Factor unitless
+Public Fnew As Double
+Public error As Double
+Public i As Integer
+Public Function Pipefriction(Re, Rr)
+'
+' Calculated Moody Friction Factor for fluid flows
+'
+'https://en.wikipedia.org/wiki/Darcy_friction_factor_formulae
+'
+'The log function is understood to be base-10 (as is customary in engineering fields): if x = log(y), then y = 10x.
+'Hence, Loge(10)=2.30258509299405, 2/loge(10)=0.8685889638065
+'
+Ff = -1
+i = 0
+If Re > 0 And Re <= 2000 Then
+    Ff = 64 / Re
+ElseIf Re > 2000# And Re < 90000000000# And Rr > 0 And Rr < 0.01 Then
+    Ff = 0.015
+    Do
+        ' Fnew = 1 / (2 * Log10(Rr / 3.7 + 2.51 / (Re * Ff ^ 0.5))) ^ 2
+        Fnew = 1 / (0.8685889638065 * Log(Rr / 3.7 + 2.51 / (Re * Ff ^ 0.5))) ^ 2
+        error = Abs(Fnew - Ff) / Fnew
+        Ff = Fnew
+        i = i + 1
+    Loop Until error < 0.00001
+End If
+Pipefriction = Ff
+End Function
+'Static Function Log10(X)
+'    Log10 = Log(X) / Log(10#)
+'End Function</code>++++
+As can be seen in the wiki page, [[https://en.wikipedia.org/wiki/Darcy_friction_factor_formulae#Colebrook%E2%80%93White_equation|Darcy friction factor formulae]], there are reasonably accurate equations that approximate the Colebrook equation that are available that do not require iterations to solve.  I believe the VBscript is simpler and not an approximation.....
+====Excel Conditional Formatting Applies to Field Changing Unexpectedly====
+MSExcel unnecessarily and annoyingly changes conditional formatting ranges.
+The options menu, advanced options, Editing options, unselect Extend data range formats and formulas reputedly stops this behavior.  Unfortunately, it also stops the automatic copying of formula when inserting new rows or adding new lines to the bottom of an existing list.
+References:
+  *[[https://answers.microsoft.com/en-us/msoffice/forum/all/excel-conditional-formatting-applies-to-field/9fa1d051-0599-4763-9782-87dc118fbfa2|Excel Conditional Formatting Applies To Field Changing Unexpectedly]]
+  *[[https://support.microsoft.com/en-us/office/advanced-options-33244b32-fe79-4579-91a6-48b3be0377c4|MSExcel Advanced Options Description]]
 ======MS Word======