If we place a obstacle in the fluid flow, fluid will be circulating behind the obstacle. What is this called? This might be a wake or recirculation region. What is the difference?
Pump2 primes Pump1. So far OK. Pump1 turns on, and both for recirculation and taking some load off Pump2. Probably OK thanks to recirculation making up flow difference. Pump2 turns off. This is where things get a little hairy since Pump1 might actually end up driving Pump2 and Pump2 may not handle that. solution is a bypass of pump2 with a ...
The other advantage is to prevent recirculation inside the impeller at off design conditions (outside of the optimal point). But my original question was directed at the diffusers at the outlet of the impeller.
You should use filter method, which accepts a callback function. The filter () method creates a new array with all elements that pass the test implemented by the provided function. Also, use typeof operator in order to find out the type of item from array. The typeof operator returns a string indicating the type of the unevaluated operand.
The shape of the filter_list was only a suggestion, so that it is readable. I wouldn't call the filters filter_1, filter_2, etc. but in such a way, that it's clear what the purpose of the filter is. Within each filter it should be clear what column of the data.frame is targeted and what values are selected.
You create your filter over A:G by condition of K:K, like you had and you filter the result for the columns in your filtered range being equal to the given columns.