General comments

The paper compares different approaches for simulating wind turbine wakes. Meshing the blade geometry is compared to the less expensive actuator line (ACL) method, and scale-resolving DDES is compared to URANS. In-depth analysis includes comparison to measurements and focuses on the blade wake and tip vortex prediction.

The paper is long and very detailed, however it is well-structured and the reader is rewarded with insight on numerous fronts: Flow physics, the pros and cons of the considered approaches, the importance of mesh resolution and high-quality schemes. The authors go to significant effort to understand and explain their simulation results, a particularly noteworthy aspect of the paper. For example, the steps taken to separate influence factors provide clarity on the principal source of error in the ACL method.

The English is generally excellent, although some word choices should be revised for clarity (see “technical corrections”).

This reviewer recommends publication subject to minor revisions.

Specific comments

1. Lines 220-225: The localised Bernoulli equation in the BDES is not Galilean invariant. Please add a few lines explaining how this is overcome for the moving geometry.
2. Lines 315-318: I haven’t understood the boundary conditions on the front and rear part of the nacelle. Is this just a rotating wall velocity BC, or something else? Please adjust for clarity.
3. In the sections comparing simulation and PIV, key information is buried too late in the text. Please place explanations of the following more prominently: Are the results instantaneous or phase-averaged in the CFD and PIV? How do the locations in degrees relate to the position of the blade (e.g. are the snapshots always taken when the blade is at “top dead centre”?). Information on whether data is instantaneous or phase-averaged should be added to the relevant figure captions.
4. Figure 17 and discussion: Please explain whether the radial position of the profiles is adjusted to the actual vortex location in each snapshot, or at a fixed location. This is important, as you observe later, since the vortex location wanders from cycle to cycle.
5. Lines 848-849: Please expand slightly. What aspect of BDES causes “almost implicit LES behaviour in flows of solid rotation”? The sigma-model form of the SGS mode?

Technical corrections

1. The word “though” is often used incorrectly. “However” or “nonetheless” are suggested instead, e.g. Lines 369, 596, 678, 877
2. Line 508: origin -> originate
3. Line 608: “pretend” isn’t the right word, suggest “occur”
4. Line 630: on behalf of -> for
5. Line 682: matter -> consequence
6. Line 707: but -> except
7. Lines 726-727: “which results that” is unclear, please revisit this sentence

This manuscript presents an exhaustive numerical investigation of the near wake of the MEXICO rotor operating in stalled conditions including a comparison with available measurements. Although, the case studied is not very representative of modern wind turbines, it is still very relevant to explore how various numerical methods perform for rotating blades operating in stalled conditions.

 The manuscript is generally clear and well-structured but is very long. The main reason for the long length of the document is that the authors sets out several goals: validation, comparison and evaluation of the performance of numerical methods in stall, description of near wake flow features etc. It would probably improve the manuscript if it was focused on only a subset of these objectives.

Specific comments:

I suggest removing all the results with the standard ACL (ACL-polars) method or redoing the simulations with appropriate airfoil data. It does not make much sense to make a comparison with uncorrected 2D airfoil data that you already know will not work well for this case

In the abstract you write that “…. URANS method performed very poorly”. This is not covering the actual shown performance of the URANS and is inconsistent with what you later write in the summary (5.3.3) and the conclusions.

Line 615: What do you mean by phase averaging? Your only simulate one rotor revolution. Is it the equivalent of averaging over three blades?

Editorial comments:

In general the English writing is good but there are still many sentences in the manuscript with missing words and  there are cases with duplicate words and (nearly) duplicate sentences (e.g. line 80-85 and 850-855). I suggest a careful read through to correct them.