a plurality of sidewalls extending lengthwise along a fluid flow direction between a first end and a second end of the turbulizer, the sidewalls being spaced apart across a width of the turbulizer;

a plurality of flow channels, each said flow channel being defined between two of said sidewalls which are adjacent to one another, each said flow channel having a first open end at the first end of the turbulizer and a second open end at the second end of the turbulizer; wherein:

each one of the sidewalls, independently, has a smoothly and continuously curved profile comprising a plurality of wave forms defined along the length of the turbulizer, the wave forms comprising a plurality of alternating crests and troughs, each wave form having a wavelength and an amplitude, wherein the continuously curved profile includes inflection points, each inflection point, independently, defined at a point midway between a crest and an adjacent trough wherein wherein a convex curvature defined by the wave form transitions to a concave curvature, the continuously curved profile configured such that each inflection point of a one of the plurality of sidewalls is disposed along a longitudinal line that extends parallel to a longitudinal axis of the heat exchanger, the longitudinal line intersecting each of the inflection points of the one of the plurality of sidewalls; and

an alternating arrangement of a plurality of continuously curved profile portions;

each one of the plurality of continuously curved profile portions, independently, extending between an adjacent pair of inflection points of the continuously curved profile of the respective one of the plurality of sidewalls such that adjacent continuously curved profile portions extend on opposite sides of the longitudinal line that extends through each of the inflection points of the sidewall; and

each one of the plurality of continuously curved profile portions, independently, forms part of a non-circular shape with effect that the flow channels of the turbulizer each, independently, have an inflection point channel width, as measured along an axis that extends normal to a first sidewall of the two adjacent sidewalls that define a respective one of the flow channels at the inflection point to a second sidewall of the two adjacent sidewalls that define the respective one of the flow channels, that is at least 85-95% of a channel width of the respective one of the flow channels as measured along an axis that extends normal to the first sidewall at a respective crest or trough to the second adjacent sidewall.